,transcrib]'s ,notes3 ,und]scores 80 be=e & aft] a ^w or phrase indicate italics 9 ! orig9al text4 ,small capitals h be5 conv]t$ to ,,solid capitals4 ,illu/rations h be5 mov$ s !y d n break up p>agraphs4 ,illu/ration3 ,,ski-,,optomet] ,,ma/] ,,model #bae ,embody+ 9 a ,s+le ,in/rum5t1 9 ,conv5i5t ,=m1 ,cyl9drical & ,sph]ical ,l5ses1 9 ,comb9ation ) ,appliances = ,te/+ & ,correct+ ,muscul> ,imbalance4 ,refraction & ,muscul> ,imbalance ,z ,simplifi$ ,?r\gh ! ,use ( ! ,ski-optomet] ,by ,,daniel ,,woolf ,,woolf ,,in/rum5t ,,corporation ,,new ,,york3 #eaf ,,fif? ,,av5ue ,copyright #aiba ,by ,,woolf ,,in/rum5t ,,corporation ,publi%$ by ,,!odore ,s4 ,,holbrook ,,new ,,york ,,cont5ts ,,*apt] ,i ,page ,,ski-,,optomet] ,,con/ruction #a ,convex ,sph]ical ,l5ses #b ,op]ates & ,indicates ,automatically #f ,concave ,sph]ical ,l5ses #g ,,*apt] ,,ii ,,cyl9drical ,,l5ses #aj ,obta9+ ,correct ,focus #aa ,:y ,concave ,cyl9d]s ,are ,us$ ,exclusively #ad ,transposition ( ,l5ses #ad ,,*apt] ,,iii ,,h[ ,,! ,,ski-,,optomet] ,,assi/s ,,9 ,,refraction #ag ,! ,use ( ! ,ski-optomet] 9 ,skioscopy #ag ,a ,simplifi$ ,skioscopic ,me?od #bj ,employ+ ,sph]es & ,cyl9d]s 9 ,skioscopy #bb ,use ( ! ,ski-optomet] 9 ,subjective ,te/+ #bc ,a ,simplifi$ ,subjective ,me?od #bd ,proc$ure = ,us+ ,m9us ,cyl9d]s ,exclusively #bf ,con/ant ,att5tion ,n ,requir$ #bi ,,*apt] ,,iv ,,important ,,po9ts ,,9 ,,connection ,,) ,,! ,,use ,,( ,,! ,,ski-,,optomet] #cj ,elim9ation ( ,trial-,frame ,discom=t #cj ,rigidity ( ,con/ruction #ca ,h[ to ,place ! ,ski-optomet] 9 ,position #cb ,clean+ ! ,l5ses #cc ,accuracy ,assur$ 9 ,e ,te/ #cd ,built to ,la/ a ,lifetime #ce ,,*apt] ,v ,,cond5s$ ,,proc$ure ,,= ,,mak+ ,,sph]e ,,& ,,cyl9d] ,,te/ ,,) ,,! ,,ski-,,optomet] #cg ,subjective ,di/ance ,te/ #cg ,subjective ,read+ ,te/ #dj ,,*apt] ,,vi ,,muscul> ,,imbalance #da ,! ,action ( ,prisms #db ,! ,phoromet] #dc ,! ,maddox ,rod #dd ,proc$ure = ,mak+ ! ,muscle ,te/ #de ,b9ocul> & ,monocul> ,te/ #dg ,,*apt] ,,vii ,,! ,,b9ocul> ,,muscle ,,te/ #dh ,made ) ! ,maddox ,rod & ,phoromet] #dh ,esophoria & ,exophoria #ej ,mak+ ,muscle ,te/ ,be=e & ,aft] ,optical ,correction #eb ,:5 to ,consid] ,correction ( ,muscul> ,imbalance #ec ,f\r ,me?ods = ,correction ( ,muscul> ,imbalance #ed ,! ,rot>y ,prism #ed ,use ( ! ,rot>y ,prism 9 ,b9ocul> ,muscle ,te/s #ef ,,*apt] ,,viii ,,! ,,monocul> ,,duction ,,muscle ,,te/ #eh ,made ) ,bo? ,rot>y ,prisms #eh ,locat+ ! ,faulty ,muscle #eh ,adduction #ei ,abduction #fa ,sup]duction #fb ,subduction #fc ,proc$ure = ,monocul> ,muscle ,te/+ #fd ,diagnos+ a ,specific ,muscle ,case #fe ,,*apt] ,,ix ,,fir/ ,,me?od ,,( ,,treatm5t--,,optical ,,correction #gj ,esophoria #gj ,treatm5t = ,correct+ ,esophoria 9 ,*ildr5 #gb ,h[ ,optical ,correction ,t5ds to ,decrease #f ,esophoria 9 a ,*ild #gd ,,*apt] ,x ,,second ,,me?od ,,( ,,treatm5t--,,muscul> ,,ex]cise #ge ,made ) ,two ,rot>y ,prisms & ,r$ ,maddox ,rod #ge ,exophoria #ge ,an ,assum$ ,case #gh ,effect ( ,muscul> ,ex]cise #hj ,home ,treatm5t = ,muscul> ,ex]cise--,squ>e ,prism ,set ,us$ 9 ,conjunction ) ! ,ski-optomet] #hb ,,*apt] ,,xi ,,?ird ,,me?od ,,( ,,treatm5t--,,prism ,,l5ses #hd ,:5 & ,h[ ,employ$ #hd ,prism ,r$uction ,me?od #he ,,*apt] ,,xii ,a ,,cond5sation ,,( ,,previ\s ,,*apt]s ,,on ,,! ,,proc$ure ,,= ,,muscle ,,te/+ ,,) ,,! ,,ski-,,optomet] #hg ,f\r ,me?ods ( ,treat+ an ,imbalance ,case :5 ! ,prec$+ ,"o ,fails #ij ,prisms #ib ,cyclophoria #ib ,,*apt] ,,xiii ,,cyclophoria #ic ,made ) ,maddox ,rods & ,rot>y ,prisms #ic ,,*apt] ,,xiv ,,cycloduction ,,te/ #ii ,made ) ! ,comb9$ ,use ( ! ,two ,maddox ,rods #ii ,treatm5t = ,cyclophoria #ajb ,,*apt] ,,xv ,,movem5ts ,,( ,,! ,,eyeballs ,,& ,,_! ,,anomalies #aje ,monocul> ,fixation #aje ,b9ocul> ,fixation #ajf ,or?ophoria #ajg ,het]ophoria #ajg ,squ9t #ajh ,v>ieties ( ,het]ophoria & ,squ9t #aji ,,*apt] ,,xvi ,,law ,,( ,,projection #aad ,suppression ( ,image #aae ,monocul> ,diplopia #aae ,table ( ,diplopia #aaf ,movem5t ( ,ea* ,eye ,s+ly #aag ,subsidi>y ,actions #aah ,field ( ,action ( ,muscles #abj ,direction ( ! ,gaze #abj ,prim>y ,position--,field ( ,fixation #aba ,b9ocul> ,movem5ts #aba ,p>allel ,movem5ts #abb ,lat]al ,rotators #abc ,eye ,associates #abd ,movem5ts ( ,conv]g5ce #abe ,movem5ts ( ,div]g5ce #abe ,v]tical ,div]g5ce #abf ,or?ophoria #abf ,het]ophoria #abf ,subdivisions #abf ,,*apt] ,,xvii ,,symptoms ,,( ,,het]ophoria #abh ,treatm5t #acj ,de/rophoria & ,laevophoria #acb ,! dem&s ( ! day = maximum effici5cy 9 ! refract+ _w are l>gely acc\ntable = ! inception1 cont9u\s improvem5t & ultimate developm5t ( ! ma/] model ,ski-optomet]4 ,! pres5t volume1 deal+ ) ! in/rum5t's di/9ctive op]ative features1 has be5 prep>$ n only = ,ski-optomet] us]s1 b also = ^? int]e/$ 9 ! simplification ( refraction & muscul> imbalance4 ,! au?or is indebt$ = invaluable c\nsel1 to ,l\is ,j4 ,am5o1 ,m4,d41 ,new ,york4 ,e4 ,le,roy ,ry]1 ,o4,d41 ,new ,york4 ,jos4 ,d4 ,heitg]1 ,m4,d41 ,l\isville1 ,ky4 ,w4 ,b4 ,ne$les1 ,n4,d41 ,kansas ,city1 ,mo4 ,,introductory ,:ile 9 a measure ! conv5tional trial-case /ill s]ves its purpose1 s mu* ( ! refractioni/'s "t is consum$ ?r\gh ! me*anical process ( individually transf]r+ ! trial-case sph]es & cyl9d] l5ses1 t f> too little ?\ght is giv5 to muscul> imbalance1 not)/&+ its importance 9 all refraction cases4 ,dr4 ,samuel ,!ibold1 ( ,johns ,hopk9s ,univ]sity1 9 a rec5t address be=e ! ,am]ican ,m$ical ,association1 /at$ t ! av]age refractioni/ 0 incl9$ to devote an excess ( "t to g5]al refraction1 completely ov]look+ ! important te/ & correction ( muscul> imbalance4 ,if ! latt] is to be at all consid]$1 g5]al refraction mu/ be simplifi$--)\t impair+ its accuracy--a result t is greatly facilitat$ ?r\gh ! use ( ! ,ski-optomet]4 ,"o mu/ admit t t$i\sly select+ ! requir$ trial-case l5s--:e!r sph]e1 cyl9d] or prism--wat*+ ! /amp$ numb] on ! h&le--cont9ual wip+ & ins]t+ ea* individual l5s 9 a trial-frame is a "t-consum+ practise4 ,?is is readily ov]come1 h[ev]1 ?r\gh ! employm5t ( ! ,ski-optomet]4 ,9 a ^w1 ! ,ski-optomet] is practically an automatic trial-case1 be>+ ! same relation to ! refract+ room z ! accept$ labor & "t-sav+ devices ( ! day be> to ! comm]cial _w4 ,! pres5t volume has accord+ly be5 publi%$1 n alone 9 ! int]e/ ( ^? possess+ a ,ski-optomet]1 b also = ^? int]e/$ 9 atta9+ ! highe/ po9t ( effici5cy 9 ! "w ( refraction & muscul> imbalance4 ,illu/ration3 ,ski-optomet] ,l5s ,batt]y 7almo/ actual size7 %[+ h[ sph]e & cyl9d] l5ses are procur$4 ,aft] obta9+ ,,f9al results1 y\r prescription is automatically regi/]$1 ,,all ,,ready = y to transcribe4 ,fig4 #a--,! ?ree "t-sav+ moves necess>y 9 ! op]ation ( ! ,ski-optomet]4 ,,*apt] ,i ,,ski-,,optomet] ,,con/ruction ,a f> bett] und]/&+ ( ! in/rum5t w be secur$ if ! refractioni/ possess+ a ,ski-optomet] w place x be=e him1 work+ out ea* op]ation & exp]im5t /ep by /ep 9 its prop] r\t9e4 ,! ?ree moves z outl9$ 9 ,fig4 #a %\ld fir/ be ?\ghtfully /udi$ & ! me?od ( obta9+ ! sph]es & cyl9d]s c>efully obs]v$4 ,illu/ration3 ,fig4 #b--,to ,obta9 ,plano4 #a--,set sph]ical indicator at 8#jjj0 z illu/rat$ above4 #b--,set cyl9d] indicator to 8#j04 #c--,set po9t] ( supplem5t>y disk at 8op504 ,! in/rum5t %\ld !n be set at z]o or 8plano10 a position indicat$ by ! appe>ance ( ! ?ree 8#j #j #j0 at ! sph]ical regi/]1 9 conjunction ) "o 8#j0 or z]o1 = ! cyl9d] at its regi/]1 m>k$ 8,,cc ,cyl40 ,aft] ?is move1 ! supplem5t>y disk's po9t] %\ld be set at 8op50 7,fig4 #b74 ,illu/ration3 ,fig4 #c--,to obta9 sph]icals1 turn ?is ,s+le ,reel z %[n by dott$ f+]4 ,?is assures an automatic & simultane\s regi/ration at sph]e indicator ( focus ( l5s appe>+ at sight op5+4 ,,convex ,,sph]ical ,,l5ses ,a c>eful /udy w %[ t ! ,ski-optomet]'s sph]ical l5ses are obta9$ by m]ely turn+ ! small] reel 7,fig4 #c74 ,! fir/ outw>d turn ( ?is reel1 t[>d ! temporal side ( ! in/rum5t1 draws into position 9 regul> ord] ! sph]ical l5ses 4#be1 4#ej1 4#ge1 & #a4;,d41 z %[n 9 ,fig4 #c;a4 ,illu/ration3 #c-;,a--,out] sph]ical reel conta9+ ,cx4 sph]icals f 4#jbe to #a4jj;,d & a blank4 ,illu/ration3 #c-;,b--,inn] sph]ical disk conta9+ ,cx4 sph]icals1 automatically turns )9 #c-;,a4 ,illu/ration3 #c-;,c--,supplem5t>y sph]ical disk4 ,by means ( a conceal$ too? ge>1 an inn] disk is automatically pick$ up1 plac+ its fir/ l5s #a4be;,d 9 position 7,fig4 #c;b74 ,?is #a4be;,d sph]ical l5s rema9s /ation>y :ile ! out] disk aga9 revolves1 add+ to x ! orig9al 4#be1 4#ej1 4#ge & #a4;,d41 ! latt] totall+ #b4be;,d4 ,at ?is po9t1 ! in/rum5t aga9 automatically picks up its inn] disk1 !reby plac+ its second l5s1 #b4ej;,d1 9 position4 ,illu/ration3 ,fig4 #d--,) ! reappe>ance ( 8#jj0 at sph]e indicator1 a rapid increase or decrease ( #a4be is accurately & spe$ily atta9$4 ,in/ead ( us+ int]m$iate /r5g?s 9 mak+ an exam9ation1 x is frequ5tly desirable to make su* ext5d$ *anges z #a4be;,d to #b4ej;,d4 ,) ! ,ski-optomet]1 ! refractioni/ w note t two :ite z]os appe>$ at ! sph]ical regi/] 9 connection ) #a4be1 & aga9 ) #b4ej4 ,a rapid outw>d turn ( ! sph]ical reel t[>d ! temporal side to ! po9t ( ! reappe>ance ( ! two z]os w %[ #c4ge;,d2 or1 if increas$ p[] is /ill desir$1 a rapid turn w draw #e4;,d4 into position 7,fig4 #d74 ,turn+ ! reel inw>d t[>d ! nasal side w likewise decrease its convex p[]4 ,9 brief1 ea* "o ( ^! l5ses1 %[+ _! foci 9 conjunction ) ! two :ite z]os1 are signals indicat+ ! rapid increase or decrease ( "o & "o-qu>t] diopt]4 ,aft] cont9u+ to #f;,d41 ! next turn automatically %[s z]o 7or 8plano071 ! orig9al />t+ po9t1 :i* is aga9 indicat$ by ! ?ree :ite z]os4 ,?r\gh ! turn ( ! s+le reel--an exclusive ,ski-optomet] feature--all convex sph]ical l5ses h n[ be5 atta9$ 9 qu>t]s up to #f4;,d1 practically cov]+ n9ety p]c5t ( all refraction cases4 ,illu/ration3 ,fig4 #e--,) supplem5t>y disk po9t] set at #f ,sph41 ?is places an additional #f4;,d sph]ical l5s at sight op5+1 ext5d+ in/rum5t's total convex sph]ical p[] to #ab4;,d4 ,%\ld /ill great] p[] be desir$1 ! small po9t] at ! out] edge ( ! in/rum5t %\ld be set at #f sph]e 7,fig4 #e74 ,?is controls a supplem5t>y disk 7,fig4 #c;c7 :i* places an additional #f;,d4 l5s be=e ! orig9al range ( l5ses previ\sly ref]r$ to1 ?us increas+ ! maximum p[] to #ab;,d4 ,if /ill great] /r5g? is requir$1 any additional trial-case l5s may be add$1 a cell be+ provid$ = t purpose on ! =w>d plate ( ! in/rum5t4 ,,op]ates ,,& ,,indicates ,,automatically ,z previ\sly expla9$1 9 us+ ! ,ski-optomet]1 x is only necess>y to rememb] t ea* outw>d turn ( ! s+le reel t[>d ! temporal side ( ! pati5t increases ! plus p[]1 :ile ! rev]se turn t[>d ! pati5t's nose decreases x4 ,9 fact1 no att5tion ne$ ev] be giv5 ! regi/] until ! requir$ sum-total is secur$1 x only be+ necess>y to turn ! s+le reel 9 ord] to be assur$ ( ! unv>y+ & accurate op]ation ( ! in/rum5t4 ,= conv5i5ce1 ! cont\r or upp] edge ( ! plate cov]+ ! sph]ical reel has be5 made to fit ! index f+] 7,fig4 #c74 ,h5ce ! op]ator %\ld note t x requires b "o complete turn f extreme side to side1 r ?an a numb] ( %ort turns1 9 ord] to br+ ea* individual l5s into position1 ?us obta9+ ! full advantage ( ! automatic spr+-/op4 ,?is likewise p]mits ! refractioni/ to op]ate ! ,ski-optomet] ev5 ?\gh ! room is 9 total d>kness4 ,,concave ,,sph]ical ,,l5ses ,ano!r simple & exclusive ,ski-optomet] advantage wor?y ( note is ! me?od employ$ 9 obta9+ concave1 sph]ical l5ses4 ,in/ead ( employ+ a batt]y ( concave l5ses simil> to ! convex batt]y previ\sly describ$1 ! in/rum5t's op]ation is greatly simplifi$ ?r\gh ! use ( a neutraliz+ process4 ,9 %ort1 ! ,ski-optomet] only conta9s two concave l5ses to obta9 its entire s]ies--namely1 a -#f4;,d & a -#ab4;,d sph]e 7,fig4 #c;c7--fir/ sett+ ! po9t] ( ! supplem5t>y disk at -#f4 sph]e1 !n sett+ ! indicator ( ! sph]ical batt]y at #f4 ,?us z]o 7or plano7 is obta9$1 ! plus neutraliz+ ! m9us4 ,by m]ely turn+ ! plus or convex sph]ical reel inw>d1 or t[>d ! pati5t's nose1 ! convex p[] is !n decreas$1 naturally increas+ ! concave value or total m9us l5s p[]4 ,= example1 if ! sph]ical indicator %[s #e4;,d1 :5 ! -#f;,d4 l5s is plac$ beh9d x1 ! l5s value at ! sight op5+ w be -#a;,d 7,fig4 #f74 ,if requir$1 ! refractioni/ may cont9ue on ?is plan until only ! -#f;,d4 l5s rema9s4 ,illu/ration3 ,fig4 #f--,) ?is indicator ( supplem5t>y disk1 set at -#f4;,d4 ,sph4 & sph]ical indicator at #e4;,d--l5s value at sight op5+ is -#a4;,d4 ,sph4 ,?is simple arrangem5t makes x possible to op]ate ! ,ski-optomet] ) b ,s+le ,reel = bo? plus & m9us sph]icals4 ,%\ld concave p[] /rong] ?an -#f;,d4 be desir$1 by plac+ ! po9t] ( ! supplem5t>y disk at -#ab;,d4 ,sph4 & proce$+ to neutralize z be=e1 all ! concave p[]s up to -#ab;,d4 9 qu>t]s are simil>ly obta9$4 ,= ! conv5i5ce ( ! op]ator1 all m9us or concave sph]ical p[]s are indicat$ 9 r$2 :ile plus1 or convex p[]s1 are indicat$ 9 :ite4 ,! in/rum5t is also provid$ ) an opaque or blank disk :i* is br\ght into position be=e ! sight op5+ by sett+ ! po9t] ( ! supplem5t>y disk at 8%ut0 7,fig4 #c;c47 ,summ+ up1 all plus & m9us sph]ical p[]s h be5 atta9$ f z]o to #ab;,d4 9 qu>t]s1 practically ?r\gh ! turn ( ! s+le reel--a simplicity ( op]ation l>gely responsible = ,ski-optomet] supremacy4 ,,*apt] ,,ii ,,cyl9drical ,,l5ses ,x is commonly admitt$ t sett+ ea* trial-case cyl9drical l5s at a common axis is ! mo/ t$i\s "p ( refraction4 ,! automatic cyl9d]1 "o ( ! ,ski-optomet]'s late/ & di/9ctly exclusive features1 n only ov]comes ?is annoyance b also avoids ! ne$ ( individually transf]r+ ea* cyl9drical l5s accord+ to ! v>y+ /r5g?s4 ,illu/ration3 ,fig4 #g--,once y set ! axis indicator z %[n by dott$ f+]s1 ea* cyl9drical l5s 9 ! in/rum5t automatically positions itself exactly at t axis1 z indicat$ by ! arr[4 ,by m]ely sett+ ! ,ski-optomet]'s axis indicator 7,fig4 #g71 ea* cyl9drical l5s 9 ! in/rum5t automatically positions itself1 s t x w appe> at ! op5+ at ! exact axis indicat$4 ,?is is readily accompli%$ by plac+ ! ?umb on ! small knob1 or h&le ( ! axis indicator1 draw+ x outw>d s z to release x f spr+ t5sion4 ,! indicator may !n be set at any desir$ axis2 &1 on releas+ ! h&le1 e cyl9d] 9 ! in/rum5t becomes lock$1 mak+ x impossible = any l5s to appe> at an axis o!r ?an ! "o specifi$ by ! indicator4 ,?is insures ! absolute accuracy ( ! axis ( e cyl9d] z x appe>s be=e ! pati5t's eye4 ,subsequ5t %ift+ ( ! axis ev5 to a s+le degree is impossible1 al?\gh x is a common occurr5ce :]e trial-case l5ses are employ$4 ,,obta9+ ,,correct ,,focus ,aft] sett+ ! axis indicator1 ! only rema9+ move is to obta9 ! correct cyl9drical /r5g? or focus4 ,?is is readily accompli%$ by m]ely turn+ ! ,ski-optomet]'s l>g] or extreme out] s+le reel1 :i* conta9s concave cyl9drical l5ses f 4#be;,d to #b;,d 9 qu>t]s 7,fig4 #h;a74 ,x %\ld aga9 be borne 9 m9d t a d[nw>d turn increases concave cyl9d] p[]1 :ile an upw>d turn decreases x4 ,! op]ation ( ! cyl9d] reel is greatly facilitat$ by c>efully not+ position ( ?umb & index f+] 7,fig4 #h74 ,?us accuracy ( result1 simplicity ( op]ation & ! sav+ ( mu* valuable "t is inv>iably assur$4 ,illu/ration3 ,fig4 #h;,a--,inn] cog-:eel con/ruction1 %[+ arrangem5t ( ,ski-optomet] cyl9d]s4 ,?is simple con/ruction assures accuracy & avoidance ( ! slighte/ %ift+ ( axes4 ,z ea* cyl9d] appe>s be=e ! pati5t's eye1 x simultane\sly regi/]s its focus at ! indicator m>k$ 8,,cc ,,cyl0 %[n 9 ,fig4 #h4 ,exam9ations ( great] accuracy c\ld n possibly be made ?an ^? obta9$ ?r\gh ! ,ski-optomet]1 h5ce no refractioni/ %\ld hesitate to employ x ?r\gh\t an entire exam9ation--:]ev] trial-case l5ses are us$4 ,! range ( ! ,ski-optomet]'s cyl9d] l5s batt]y includes up to #b;,d4 9 qu>t]s4 ,an axis scale & a cell is locat$ at ! back ( ! in/rum5t = ins]tion ( an additional trial-case cyl9d] l5s1 :5 /rong] cyl9drical p[] is requir$4 ,= example1 if an additional -#b;,d4 cyl9d] is add$1 x w increase ! range up to #d;,d4 cyl9d]2 or if twelf?s are desir$1 a #j4ab;,d4 cyl9d] l5s may be ins]t$4 ,9 ?is connection1 x is int]e/+ to note t consid]able exp]im5t+ ) twelf?s 9 ! ,ski-optomet] prov$ !m to be ne$less1 inasmu* z ! in/rum5t's cyl9drical l5ses set directly next to ! pati5t's eyes ov]come all possible loss ( refraction1 z expla9$ 9 a lat] p>agraph4 ,illu/ration3 ,fig4 #h--,turn ?is ,s+le ,reel z %[n by dott$ f+] to obta9 cyl9drical l5ses1 :i* simultane\sly regi/] _! focus z !y appe>4 ,ea* l5s also automatically positions itself at axis designat$4 ,,:y ,,concave ,,cyl9d]s ,,are ,,us$ ,,exclusively ,! ,ski-optomet] conta9s only concave cyl9d]s1 z x is univ]sally admitt$ t convex cyl9d]s are n ess5tial = te/+ purposes4 ,9 fact1 concave cyl9d]s %\ld alone be us$ 9 mak+ an exam9ation1 ev5 :]e a complete trial-case is employ$4 ,to repeat "o ( ! fir/ rules ( refraction3 8,z mu* plus or z little m9us sph]ical p[] z pati5ts w accept1 comb9$ ) weake/ m9us cyl9d]1 simplifies ! "w ( refraction & insures accuracy )\t "t-wa/e40 ,aft] an exam9ation ) ! ,ski-optomet] is complet$1 ! total result ( plus sph]e & m9us cyl9d] may be transpos$ if desir$1 ?\gh 9 mo/ in/ances x is pref]able to prescribe ! exact f9d+s indicat$ by ! in/rum5t4 ,?is w also avoid e possibility ( error1 elim9at+ responsibility :]e "o is n famili> ) transposition--s9ce1 aft] all1 x is ! duty ( ! optician to ?or\ghly und]/& t "p ( ! "w4 ,,transposition ,,( ,,l5ses ,x is commonly und]/ood t transposition ( l5ses is m]ely *ange ( =m1 b n ( value4 ,= example1 a l5s #a4jj sph4 -4#ej cyl4 axis #ahj may be transpos$ to its equival5t1 :i* is 4#ej sph4 4#ej cyl4 axis #ij4 ,! accept$ =mula 9 ?is special in/ance is z foll[s3 ,algebraically add ! two quantities = ! new sph]e1 reta9 ! p[] ( ! orig9al cyl9d]1 b *ange its sign & rev]se its axis #ij degrees4 ,apply+ ?is rule1 a l5s 4#ge sph4 -4#be cyl4 axis #ahj1 is equival5t to 4#ej sph4 4#be cyl4 axis #ij4 ,simil>ly1 a l5s #a4jj sph4 -#a4jj cyl4 axis #ahj is equival5t to #a4jj cyl4 axis #ij4 ,"o ( ! difficulties 9 transpos+ is 9 rev]s+ ! axis4 ,9 su* cases1 x is well to memorize ! foll[+ simple rule3 ,to rev]se ! axis ( any cyl9drical l5s conta9+ ?ree num]als--add ! fir/ two toge!r & c>ry ! la/4 ,= example1 f #aje to #ahj degrees1 etc43 #aje ,add--"o & 8#j0 equals #a ,!n c>ry ! #e #ae #abj ,add--"o & two equals #c ,!n c>ry ! #j #cj #acj ,add--?ree & "o equals #d ,!n c>ry ! #j #dj #aej ,add--five & "o equals #f ,!n c>ry ! #j #fj #afe ,add--six & "o equals #g ,!n c>ry ! #e #ge #ahj ,add--eight & "o equals #i ,!n c>ry ! #j #ij ,to transpose :]e !re are b two num]als1 #ij %\ld be add$4 ,9 us+ ! ,ski-optomet]1 x is absolutely unnecess>y to transpose ! f9al result ( an exam9ation2 m]ely write ! prescription z in/rum5t indicates4 ,! idea t plus sph]e comb9$ ) m9us cyl9d]1 or ! rev]se1 is an incorrect me?od ( writ+ a prescription1 has long s9ce be5 disprov$4 ,,*apt] ,,iii ,,h[ ,,! ,,ski-,,optomet] ,,assi/s ,,9 ,,refraction ,! con/ruction ( ! ,ski-optomet] has n[ be5 fully expla9$1 & ! read] realizes t s9ce ! in/rum5t conta9s all ! l5ses necess>y 9 mak+ an exam9ation1 great] op]ative facility is af=d$ ?r\gh its use ?an :]e ! trial-case l5ses are employ$4 ,! ,ski-optomet] is 8an automatic trial-case0 9 ! broade/ s5se ( ! t]m1 :olly sup]s$+ ! conv5tional trial-case4 ,x %\ld !re=e be employ$ ?r\gh\t an entire exam9ation1 :]ev] trial-case l5ses 7 =m]ly us$4 ,to fully realize its labor sav+ value 9 obta9+ accurate exam9ation results1 x is only necess>y to recall ! t$i\s me?od ( individually h&l+ & transf]r+ ea* l5s f ! trial-case to ! trial-frame1 wat*+ ! /amp$ numb] on ea* l5s h&le1 wip+ ea* l5s & 9 ! case ( cyl9drical l5ses sett+ ea* "o at a designat$ axis--all be+ ne$less /eps :]e ! ,ski-optomet] is employ$4 ,,! ,,use ,,( ,,! ,,ski-,,optomet] ,,9 ,,skioscopy ,9 skioscopy1 ! ,ski-optomet] (f]s ! refractioni/ assi/ance ( ! mo/ valuable "*4 ,= example1 assum+ t extreme motion 9 ! opposite direction ) plane or concave mirror is obta9$ ) a #a4be;,d4 sph]ical l5s be=e ! pati5t's eye2 by quickly turn+ ! ,ski-optomet]'s s+le reel until ! two :ite z]os aga9 appe>1 #b4ej;,d is secur$1 z expla9$ 9 ! previ\s *apt]4 ,if ?is cont9ues to give too mu* 8aga9/ motion10 ! l5s p[] %\ld be quickly increas$ to #c4ge or #e4jj;,d if necess>y 7,fig4 #d74 ,%\ld ! latt] reveal a %ad[ 9 ! rev]s$ direction1 ! refractioni/ is assur$ t x is ! weake/ l5s t w cause its neutralization4 ,practically b few l5ses h be5 us$ to obta9 ! f9al result prov+ ! in/rum5t's importance & "t-sav+ value 9 skioscopy1 & demon/rat+ ! simplicity ) :i* t$i\s transf]5ce ( trial-case l5ses is avoid$4 ,fur!rmore1 x %\ld be not$ t :]e ! ,ski-optomet] is us$ 9 skioscopy1 x is n necess>y to remove ! ret9oscope f ! eye or to con/antly locate a new reflex ) ea* l5s *ange4 ,?is p]mits a direct comp>ison ( ! f9al l5s & elim9ates ! usual difficulty 9 ma/]+ skioscopy4 ,! *ief cause ( ?is difficulty is due to ! fact t ! transf]r+ ( ! trial-case l5ses makes x practically impossible = ! /ud5t to det]m9e :e!r ! previ\s l5s caus$ m 8)0 or 8aga9/0 motion4 ,illu/ration3 ,fig4 #i--,! ,woolf oph?almic bracket4 ,a conv5i5t & portable accessory 9 skioscopy & muscle te/+2 c be us$ ) or )\t ,greek cross4 ,:]e ! indirect me?od is employ$ 9 skioscopy1 be/ results are secur$ ?r\gh ! use ( ! ,woolf oph?almic bracket & conc5trat$ filam5t lamp1 toge!r ) an iris diaphragm *imney4 ,! latt] p]mits ! r$uction or increase ( ! am\nt ( light ent]+ ! eye1 z x is agre$ t a l>ge pupil requires less light1 a small pupil requir+ m light4 ,! bracket ref]r$ to p]mits ! op]ator to sw+ ! light into any desir$ position 7,fig4 #i71 :ile ! iris diaphragm *imney s]ves z a %utt]4 ,?is app>atus may also be employ$ = muscle te/+1 z describ$ 9 a subsequ5t p>agraph4 ,a ,,simplifi$ ,,skioscopic ,,me?od ,9 us+ ! ,ski-optomet]1 in/ead ( work+ =ty in*es away f ! pati5t 9 skioscopy & d$uct+ #a4;,d41 ! refractioni/ w f9d x m conv5i5t to "w at a tw5ty in* di/ance1 d$uct+ #b4;,d4 ,?is work+ di/ance may be accurately measur$ & ma9ta9$ by us+ ! read+ rod accompany+ ! in/rum5t4 ,in/ead ( d$uct+ #b4;,d4 f ! total f9d+s1 h[ev]1 x is pref]able to ins]t a #b4;,d4 trial-case l5s 9 ! re> cell ( ! in/rum5t directly next to ! pati5t's eye4 ,aft] det]m9+ ! weake/ l5s requir$ to neutralize ! %ad[ 9 bo? m]idians1 ! additional #b4;,d4 l5s %\ld be remov$ & ! total result ( ! exam9ation read f ! in/rum5t's regi/]4 ,to illu/rate a case 9 skioscopy :]e sph]ical l5ses are employ$ to correct bo? m]idians1 assume t ! v]tical %ad[ requires a #a4be;,d l5s to cause its rev]sal1 :ile ! horizontal requires #b4jj;,d4 ,employm5t ( ! cu/om>y diagram1 illu/rat$ 9 ,fig4 #aj1 w\ld %[ ! pati5t requir$ #a4be sph4 4#ge cyl4 axis #ij1 :i* :5 transpos$ is equival5t to #b4jj sph4 -4#ge cyl4 axis #ahj4 ,illu/ration3 ,fig4 #aj--,:]e sph]ical l5ses are employ$ 9 skioscopy1 above indicates pati5t requires #a4be ,sph4 4#ge ,cyl4 ,axis #ij or #b ,sph4 -4#ge ,cyl4 ,axis #ahj ,x %\ld be not$ t ! total sph]ical p[] is #b4jj;,d1 z ! ,ski-optomet]'s regi/] %[s1 :ile ! diff]5ce betwe5 ! two m]idians is #ge1 :i* is ! requir$ /r5g? ( ! cyl9d]4 ,by !n turn+ ! cyl9d] reel to 4#ge1 & sett+ ! axis indicator at #ahj 7because by us+ m9us cyl9d]s1 ! axis mu/ be rev]s$7 ! pati5t %\ld read ! te/-type ) ease if ! skioscopic f9d+s are correct4 ,?us ) ! ,ski-optomet]1 x is n ev5 necess>y to le>n transposition1 s9ce ! in/rum5t automatically accompli%es ! "w1 avoid+ all possibility ( error4 ,,employ+ ,,sph]es ,,& ,,cyl9d]s ,,9 ,,skioscopy ,ano!r commonly us$ objective me?od may be employ$ ) ev5 great] facility ?r\gh ! comb9$ use ( bo? ! ,ski-optomet]'s sph]ical & cyl9drical l5ses4 ,z previ\sly sugge/$1 ins]t ! #b4jj sph]ical trial-case l5s 9 ! re> ( ! in/rum5t1 work+ at a tw5ty in* di/ance1 !n proce$ to correct ! /ronge/ m]idian fir/4 ,x 0 assum$ t x requir$ a #b4jj sph]ical to neutralize ! /ronge/1 or horizontal m]idian1 z %[n 9 ,fig4 #aj4 ,! refractioni/ %\ld !n set ! axis indicator !re)1 :i* is ! axis ( ! cyl9d]1 or #ahj4 ,x is !n m]ely a matt] ( increas+ ! ,ski-optomet]'s cyl9drical l5s p[] until ! rev]sal ( ! %ad[ 9 ! weake/ m]idian is det]m9$4 ,assum+ ?is proves to be -4#ge cyl9d]1 axis #ahj1 ! pati5t's complete prescription #b4jj sph4 -4#ge cyl4 axis #ahj1 w\ld be regi/]$ 9 ! ,ski-optomet] )\t any fur!r l5s *ange o!r ?an ! removal ( ! #b4jj work+ di/ance l5s4 ,h[ev]1 reg>dless ( ! me?od employ$1 ! ,ski-optomet] greatly simplifies skioscopy4 ,9 fact1 ! in/rum5t 0 orig9ally int5d$ to simplify ret9oscopy or skioscopy1 z ! subject %\ld be t]m$1 ! "n 8,ski-optomet]0 hav+ be5 d]iv$ f ! latt]4 ,,use ,,( ,,! ,,ski-,,optomet] ,,9 ,,subjective ,,te/+ ,9 subjective refraction1 especially :]e ! 8bett] or worse0 qu]y mu/ be decid$ by ! pati5t1 x is commonly und]/ood t ! refractioni/ is compell$ to fir/ increase & !n decrease a qu>t] ( a diopt] be=e ! f9al l5s is decid$4 ,) ! ,ski-optomet]1 ! usual ?ree f9al *anges are made 9 f> less "t ?an x takes to make ev5 "o l5s *ange f trial-case to trial-frame4 ,= example3 ,assum+1 ) a #a4be;,d sph]ical l5s be=e ! pati5t's "r eye1 he rem>ks t he 8sees bett]0 ) a #a4;,d4 :ile 4#ge;,d is n z satisfactory4 ,! refractioni/ c !n quickly return to #a4;,d41 simply turn+ ! ,ski-optomet]'s s+le reel outw>d to increase1 or backw>d to decrease1 ! l5s /r5g?4 ,s rapidly h ^! l5s *anges be5 made1 t ! pati5t quickly sees ! diff]5ce ( ev5 a qu>t] diopt]1 & quickly replies1 8bett]0 or 8worse40 ,?is is made possible because ! eye does n 8accommodate0 z quickly z ! l5s *ange made ) ! ,ski-optomet]4 ,x %\ld also be not$ t ! eye receives an image on its ret9a )9 "o-sixte5? ( a second2 o!rwise1 ! pati5t is =c$ to accommodate1 mak+ x difficult to see ! diff]5ce ( ev5 a qu>t] diopt]4 ,on ! o!r h&1 9 transf]r+ trial-case l5ses1 ) its sl[1 t$i\s proc$ure1 ! pati5t1 be+ unable to detect ! slight diff]5ce ( only a qu>t] diopt]1 unhesitat+ly replies1 8no diff]5ce10 m]ely because !y are compell$ to accommodate4 ,a ,,simplifi$ ,,subjective ,,me?od ,! foll[+ simplifi$ me?od ( proc$ure is sugge/$ = subjective te/+ ) ! ,ski-optomet]1 al?\gh z previ\sly expla9$1 ! refractioni/ may employ 8 cu/om>y me?od1 ov]com+ ! annoyance ( transf]r+ trial-case l5ses & ! sett+ ( ea* cyl9d] individually4 ,! ,ski-optomet] has be5 con/ruct$ & bas$ ^u ! gold5 rule ( refraction3 8,z mu* plus or z little m9us sph]ical1 comb9$ ) z little m9us cyl9d] p[] z ! pati5t accepts40 ,by apply+ ?is rule z 9 ! above me?od & />t+ ) #e4;,d4 sph]ical1 wat*+ ! two z]os 7,fig4 #d7 & rapidly r$uc+ #a4be;,d ea* "t1 we w assume t #a4be;,d gives #bj_/cj vision2 z a f9al result #a4;,d4 w possibly give #bj_/be vision4 ,! pati5t's att5tion %\ld next be direct$ to ! mo/ visible l9e ( type1 pref]ably conc5trat+ on ! lett] 8,e0 or ! clock dial *>t--ei!r ( :i* w assi/ 9 det]m9+ any possible a/igmatism4 ,s9ce ! ,ski-optomet] conta9s concave cyl9d]s exclusively1 ! next move %\ld be ! sett+ ( its axis indicator at #ahj1 commonly und]/ood z 8) ! rule40 ,"o %\ld !n proce$ to det]m9e ! cyl9d] l5s /r5g? by turn+ ! reel conta9+ ! cyl9drical l5ses 7,fig4 #h74 ,%\ld ! pati5t's vision fail to improve aft] ! -4#ej;,d4 cyl9d] axis #ahj has be5 employ$1 ! refractioni/1 9 seek+ an improvem5t1 %\ld !n sl[ly move ! axis indicator ?r\gh its entire arc4 ,) ! cyl9d] add$1 reg>dless ( axis1 poor vision might indicate ! abs5ce ( a/igmatism4 ,if a/igmatism exi/s1 vision w usually %[ signs ( improvem5t at "s po9t1 indicat+ ! approximate axis4 ,once ! latt] is asc]ta9$1 ! refractioni/ may readily turn ! ,ski-optomet]'s cyl9d] reel & obta9 ! correct cyl9d] l5s /r5g?1 aft] :i* ! axis indicator %\ld be mov$ 9 ei!r direction 9 ord] to obta9 ! be/ possible vision = ! pati5t4 ,! refractioni/ %\ld always aim to obta9 normal 7or #bj_/bj7 vision ) ! weake/ concave cyl9d]1 comb9$ ) ! /ronge/ plus sph]e1 or weake/ m9us sph]e4 ,,proc$ure ,,= ,,us+ ,,m9us ,,cyl9d]s ,,exclusively ,= ! b5efit ( ^? :o h nev] us$ m9us cyl9d]s exclusively 9 mak+ _! exam9ations1 we w assume t ! pati5t requires ,o4,u4 #a4;,d sph4 -#a;,d cyl4 axis #ahj = f9al correction2 ! latt]1 9 its transpos$ =m1 be+ equival5t to #a4;,d4 cyl9d] axis #ij4 ,unque/ionably ! be/ me?od is ! "o t requires ! lea/ numb] ( l5s *anges to secure ! f9al result4 ,to obta9 ?is1 ! foll[+ ord] ( l5s *ange %\ld be made3 ,fir/1 #a4;,d4 sph]e is f9ally det]m9$ & all[$ to rema9 9 place4 ,concave cyl9d]s are !n employ$ 9 qu>t]s until ! f9al results ( #a4;,d4 sph]ical1 comb9$ ) -#a4;,d4 cyl9d] axis #ahj is secur$4 ,?is necessitates ! *ange ( b f\r cyl9drical l5ses z %[n 9 r\t9e 8,a0 z foll[s3 ,,r\t9e 8,a0 ,,r\t9e 8,b0 7,made ) m9us cyl9d]7 7,made ) plus cyl9d]7 ,sph4 #a4;,d4 ,cyl4 ,axis ,sph4 #a4;,d4 ,cyl4 ,axis ,/ep #a #a4;,d4 -4#be ax4 #ahj equal to 4#ge 4#be ax4 #ij ,/ep #b #a4;,d4 -4#ej ax4 #ahj equal to 4#ej 4#ej ax4 #ij ,/ep #c #a4;,d4 -4#ge ax4 #ahj equal to 4#be 4#ge ax4 #ij ,/ep #d #a4;,d4 -#a ax4 #ahj equal to #j #a ax4 #ij ,9 brief ! me?od ( us+ m9us cyl9d]s exclusively 9 an exam9ation1 z expla9$ 9 r\t9e 8,a01 necessitates ! *ange ( ! cyl9d] l5ses only aft] ! /ronge/ plus sph]e is secur$4 ,on ! o!r h&1 not)/&+ innum]able o!r me?ods :]e plus cyl9d]s are us$1 r\t9e 8,b0 %[s t ! be/ sph]ical l5s /r5g? ! pati5t w accept1 is also fir/ det]m9$4 ,!n bo? sph]es & cyl9d]s are *ang$ 9 _! regul> ord] by gradually build+ up 9 r\t9e1 by increas+ plus cyl9d] & next decreas+ sph]e1 a qu>t] diopt] ea* "t1 until ! f9al result is secur$4 ,:ile x is conc$$ t bo? r\t9e 8,a0 & 8,b0 are ( !mselves simplifi$ me?ods1 by comp>+ r\t9e 8,a0 :]e m9us cyl9d]s are us$ ) r\t9e 8,b0 :]e plus cyl9d]s are us$ 9 _! correspond+ /eps1 ! refractioni/ w note by comp>ison t "o is ! exact equival5t & transposition ( ! o!r4 ,:]e plus cyl9d]s are employ$1 eight l5s *anges are made be=e f9al results are secur$2 :ile b f\r l5s *anges are necess>y :]e m9us cyl9d]s are us$4 ,! refractioni/ %\ld also note by comp>ison t ! use ( m9us cyl9d]s r$uces focus ( ! plus sph]e1 b only 9 ! m]idian ( ! axis4 ,x has n made ! pati5t myopic4 ,fur!rmore1 a plus cyl9d] w br+ ! focal rays =w>d1 :ile m9us cyl9d]s ?r[ !m backw>d t[>d ! ret9a4 ,?is is b ano!r reason = ! exclusive use ( m9us cyl9d]s 9 refraction4 ,! me?od ( us+ m9us cyl9d]s exclusively 9 an exam9ation1 necessitates ! *ange ( ! cyl9d] l5ses only4 ,on ! o!r h&1 ! me?od ( us+ plus cyl9d]s makes x necess>y to *ange sph]es & cyl9d]s 9 r\t9e4 ,9 brief1 s9ce us+ ! m9us cyl9d] is m]ely a matt] ( ma!matical optics1 _! use ev5 9 a trial-case exam9ation is /rongly urg$4 ,! maximum value ( ! ,ski-optomet] is fully realiz$ only :5 ! advantages ( us+ m9us cyl9d]s exclusively 9 e exam9ation is cle>ly und]/ood4 ,,con/ant ,,att5tion ,,n ,,requir$ ,) ! ,ski-optomet]1 :5 ! exam9ation is complet$1 ! sum-total ( f9al results--:e!r sph]ical1 cyl9d]1 axis1 or all comb9$--are automatically indicat$ or regi/]$ ready to write ! prescription4 ,until !n1 ! foci ( ! v>i\s l5ses t may be employ$ are ( no importance4 ,9 %ort1 9 us+ ! ,ski-optomet]1 x is n necess>y to con/antly wat* ! regi/rations dur+ exam9ations4 ,! automatic op]ation ( ! in/rum5t is an exclusive feature1 s t ! refractioni/ %\ld unhesitat+ly employ x4 ,h5ce1 by elim9at+ ! p]petual wat* on ! l5ses 9 use1 ! refractioni/ is enabl$ to give 8 undivid$ att5tion to ! pati5t r ?an to ! trial l5ses4 ,:]e a special d>k-room is us$ = skioscopic "w1 an additional wall bracket or floor /& w necessitate only ! removal ( ! in/rum5t itself4 ,?is enables ! refractioni/ to use ! ,ski-optomet] = subjective or objective "w1 )\t di/urb+ ! pati5t's correction4 ,,*apt] ,,iv ,,important ,,po9ts ,,9 ,,connection ,,) ,,! ,,use ,,( ,,! ,,ski-,,optomet] ,! ,ski-optomet] is equipp$ ) an adju/able head-re/1 p]mitt+ its l5ses to be br\ght z close z possible to ! eye )\t t\*+ ! pati5t's la%es1 a matt] ( importance 9 e exam9ation4 ,illu/ration3 ,fig4 #aa--,! nasal l9es ( ! ,ski-optomet] fit ! cont\r ( face ) mask-l p]fection1 pati5t rema9+ 9 com=table position4 ,,elim9ation ,,( ,,trial-,,frame ,,discom=t ,:]e ! ,ski-optomet] is correctly fitt$ to ! face1 ! pati5t inv>iably rema9s 9 a com=table position 7,fig4 #aa74 ,! in/rum5t is %ap$ to fit ! face l a mask1 s t ev5 ) a pupill>y di/ance ( b #ej m_/m 7t ( a *ild7 !re /ill rema9s1 )\t p9*+1 ample room = ! wide/ nose ( an adult4 ,be=e mak+ an exam9ation1 ! correct pupill>y di/ance %\ld always be obta9$ by draw+ an imag9>y v]tical l9e d[nw>d ?r\gh ! c5t] ( ea* eye f ! #ij po9t on ! ,ski-optomet] axis scale4 ,! pupill>y di/ance w !n regi/] 9 millimet]s on ! scale ( measurem5ts = ea* eye sep>ately4 ,if ! ,ski-optomet] is correctly adju/$1 ! pati5t is securely held 9 position1 ! cumb]some trial-frame be+ entirely elim9at$4 ,,rigidity ,,( ,,con/ruction ,illu/ration on foll[+ page 7,fig4 #aa;a7 %[s ! re9=c$ d\ble be>+ arms :i* hold ! ,ski-optomet] l5s batt]ies at two po9ts4 ,?is elim9ates possibility ( ! in/rum5t gett+ out ( alignm5t1 & prev5ts wabbl+ or loose work+ p>ts4 ,! broad horizontal slides %[n 9 ! cut1 move 9 & out indep5d5tly s t ! pupill>y di/ance is obta9$ = ea* eye sep>ately by turn+ ! p9ion$ h&le on ei!r side ( ! in/rum5t4 ,! scale d5otes 9 millimet]s ! ,p4,d4 f ! m$ian l9e ( ! nose outw>d1 ! total ( bo? scales be+ ! pati5t's pupill>y di/ance4 ,fig4 #aa;a also s]ves to %[ ! /aun* con/ruction ( ! base ( ! ,ski-optomet]4 ,illu/ration3 ,fig4 #aa;a--,%[+ /aun* con/ruction ( ,ski-optomet] base4 ,,h[ ,,to ,,place ,,! ,,ski-,,optomet] ,,9 ,,position ,! pati5t %\ld be plac$ 9 a com=table position ) 8*9 up10 z ?\gh look+ at a di/ant object4 ,! in/rum5t %\ld !n be rais$ or l[]$ by ! adju/able rat*et :eel ( ! bracket4 ,! wall bracket gives be/ results :5 susp5d$ f ! wall1 back ( ! pati5t1 z %[n on page #ace4 ,?is bracket %\ld be plac$ ab\t t5 in*es above ! head ( ! av]age pati5t4 ,:5 ! ,ski-optomet] is plac$ 9 position = use1 its l[] edge w b>ely t\* ! pati5t's *eeks4 ,x is sometimes advisable to reque/ ! pati5t to lightly press t[>d ! face ! horizontal b> support+ ! in/rum5t4 ,p>ticul>ly good results are secur$ :]e a *air ) a head-re/ is employ$ 9 conjunction ) ! ,ski-optomet]4 7,see illu/ration ( ,model ,refraction ,room1 ,page #aab74 ,,clean+ ,,! ,,l5ses ,! "t-wa/e ( p]petually clean+ l5ses is ov]come :]e ! ,ski-optomet] is employ$4 ,= ! conv5i5ce ( ! op]ator & protection ( ,ski-optomet] l5ses1 ! latt] are conceal$ 9 a du/-pro( cell1 ov]com+ all du/ & f+]-pr9t annoyances4 ,:5 n 9 use1 ! in/rum5t %\ld be cov]$ ) ! /&>diz$ hood =m+ "p ( ! equipm5t4 ,! in/rum5t %\ld n be tak5 ap>t "u any circum/ances4 ,to clean its l5ses1 n a s+le screw ne$ be remov$1 z ! l5ses ( ea* disk may be clean$ individually ?r\gh ! op5+ ( ! o!r disks4 ,^! op5+s are conv5i5tly indicat$ by ! :ite z]os 7,fig4 #b74 ,! ,ski-optomet] conta9s b elev5 sph]ical & eight cyl9drical l5ses on ea* side1 s t ! actual "w ( clean+ %\ld n require ov] t5 m9utes at ! mo/1 clean+ ! l5ses e o!r week prov+ q suffici5t4 ,,accuracy ,,assur$ ,,9 ,,e ,,te/ ,loss ( refraction is completely elim9at$ ?r\gh ! use ( ! ,ski-optomet]4 ,! mo/ casual exam9ation ( ! trial-frame or any o!r in/rum5t %[s t ! con/ruction necessitates ! plac+ ( ! sph]ical l5s next to ! eye ) ! cyl9d] l5s out]mo/--a s]i\s fault :olly ov]come 9 ! ,ski-optomet]4 ,n only d ! cyl9drical l5ses ( ! ,ski-optomet] set directly next to ! pati5t's eye1 ?us ov]com+ any possible loss ( refraction1 b ! /rong sph]ical l5ses ( ! supplem5t>y disk are set directly next to ! cyl9d]4 ,!re is app>5tly b a hair's di/ance betwe5 ^! l5ses2 ! two disks conta9+ ! sph]ical l5ses ( ! ,ski-optomet] likewise sett+ close toge!r4 ,9 a ^w1 ! ,ski-optomet]'s cyl9d] l5ses set directly next to ! pati5t's eye1 foll[$ by ! /rong] sph]icals1 s t ! weake/ sph]ical or 4#be 7! l5s ( lea/ importance7 sets f>!/ away4 ,?is is #c m_/m clos] ?an any trial-frame manufactur$1 h[ev]1 & at lea/ #aj m_/m clos] ?an any o!r in/rum5t--ano!r reason = implicitly rely+ on ! ,ski-optomet] = uni=mly accurate results4 ,,built ,,to ,,la/ ,a ,,lifetime ,illu/ration3 ,fig4 #ab--7;,a4 & ,b47--,?is unique1 pat5t$ split-spr+ device ( screwless con/ruction1 securely holds all movable p>ts4 ,9 case ( repair1 !y may be remov$ ) ! blade ( a knife4 ,! ,ski-optomet] is built on ! plan ( _/1 insur+ absolute rigidity & accuracy & a lifetime ( endurance4 ,p>ticul> & detail$ att5tion has be5 giv5 to ! novel means ( elim9at+ screws :i* ei!r b9d1 create friction or cont9ually "w loose1 caus+ false indications ( f9d+s on scales ( measurem5ts2 h5ce correct & accurate indications are insur$ 9 ! ,ski-optomet] by means ( a split-spr+ wa%] con/ruction simil> to t ( an automobile tire's deta*able rim 7,fig4 #ab74 ,?is pat5t$ spr+ wa%] con/ruction securely holds ! phoromet] l5ses1 ! rot>y prism & ! revolv+ cyl9d] l5s cells4 ,:5ev] necess>y1 or 9 case ( repair1 ^! p>ts may be readily remov$ ) ! blade ( a knife4 ,,*apt] ,v ,,cond5s$ ,,proc$ure ,,= ,,mak+ ,,sph]e ,,& ,,cyl9d] ,,te/ ,,) ,,! ,,ski-,,optomet] ,not)/&+ v>i\s me?ods employ$1 = bo? subjective & objective refraction1 ! foll[+ synopsis ( ! previ\s *apt]s w unque/ionably prove mo/ valuable to ! busy refractioni/1 enabl+ him to make error-pro( exam9ations 9 practically e case )\t resort+ to ! transf]5ce ( trial-case sph]e or cyl9d] l5ses4 ,a c>eful read+ ( *apt]s "o & two %\ld be made h[ev]1 s t "o may ga9 an und]/&+ z to h[ sph]es & cyl9d]s are obta9$ ) ! ,ski-optomet]4 ,,subjective ,,di/ance ,,te/ #a/--,place ,ski-optomet] 9 position1 employ+ _s level1 ?us ma9ta9+ in/rum5t's horizontal balance4 #bnd--,adju/ ! pupill>y di/ance = ea* eye individually1 by draw+ an imag9>y v]tical l9e d[nw>d ?r\gh ! c5t] ( ea* eye f ! #ij po9t on ! ,ski-optomet]'s axis scale4 ,! opaque disk %\ld be plac$ be=e ! pati5t's left eye by sett+ ! supplem5t>y disk h&le at 8%ut40 #crd--,! ,ski-optomet] l5s batt]y be=e ! pati5t's "r eye %\ld be set at 8op50 7figure #b71 :]eupon ! fir/ turn ( sph]ical l5s batt]y t[>d ! nasal side places a #f4;,d sph]e 9 position4 ,?is %\ld blur vision ( av]age pati5t4 #d?--,x is n[ only necess>y to rememb] t an outw>d turn t[>d temporal side ( ! in/rum5t increases plus sph]e p[]1 :ile a nasal turn decreases x4 ,!re=e cont9ue to r$uce convex sph]ical l5s p[] until ! l>ge lett] 8,e0 on ! di/ant te/ c>d is cle>4 ,!n reque/ pati5t to read z f> d[n z possible1--a rapid turn ( a qu>t] diopt] be+ readily accompli%$ ) ! ,ski-optomet] 7,fig4 #d74 #e?--,9 ! ev5t ( work+ d[n to 8z]o0 ) sph]es1 ! supplem5t>y disk h&le or indicator %\ld next be set at -#f4;,d sph]e1 :ile ! sph]ical reel %\ld be turn$ t[>d ! nasal side--?us build+ up on m9us sph]es 7,fig4 #f74 ,9 %ort1 ! /ronge/ plus sph]e or weake/ m9us sph]e %\ld always be det]m9$ be=e employ+ cyl9d]s4 #f?--,) ! be/ sph]ical l5s t ! pati5t w accept left 9 place1 direct att5tion to ! lett] ,e or ,f 9 ! l[e/ l9e ( type ! pati5t c see on ! di/ant te/ lett] *>t4 ,!n set axis indicator at #ahj 7,fig4 #g74 #g?--,next increase concave cyl9d] p[] until vision is improv$4 ,if vision is n improv$ aft] increas+ cyl9d] /r5g? to -4#ej axis #ahj1 m]ely rev]se ! axis to #ij4 ,if vision is improv$1 cyl9d] l5s /r5g? %\ld be increas$4 ,if n1 x %\ld be decreas$ 7,fig4 #h74 #h?--,sl[ly move axis indicator ?r\gh entire arc ( axis1 ?us locat+ be/ possible axis 7,fig4 #g74 #i?--,aft] sph]e & cyl9d] te/ ( "r eye has be5 made1 place supplem5t>y disk h&le at 8%ut40 ,!n repeat proc$ure 9 te/+ left eye4 #aj?--,aft] complet+ exam9ation = ea* eye sep>ately1 !n1 ) bo? ( ! pati5t's eyes op51 direct att5tion to l[e/ l9e ( type he c see1 conc5trat+ on ! ,e or ,f1 simultane\sly increas+ or decreas+ sph]ical p[] be=e bo? eyes4 ,! refractioni/ m]ely recalls t by turn+ ! ,ski-optomet]'s s+le reel t[>d ! temporal side1 convex sph]ical p[] is increas$1 by turn+ t[>d ! nasal side = ei!r eye1 sph]ical p[] is decreas$4 ,cyl9d] l5s /r5g? may be *ang$ 9 a l mann] be=e bo? eyes simultane\sly4 #aa?--,aft] mak+ ! di/ance te/1 !n only is x necess>y to copy ! result ( ! exam9ation z record$ by ! ,ski-optomet]4 ,,subjective ,,read+ ,,te/ ,tilt ,ski-optomet] =w>d 9 mak+ read+ te/4 ,! wide groove 9 ! horizontal b> support+ ! in/rum5t1 p]mits x to be slightly tilt$4 #ab?--,place ,ski-optomet] read+ rod 9 position ) c>d at ab\t #ad in*es4 ,close (f "o eye4 ,direct pati5t's att5tion to ! "n 8,b5jam90 pr9t$ at top ( c>d4 #ac?--,leave cyl9d] l5s 9 place4 ,proce$ z 9 di/ance te/ ) #f4;,d sph]e1 fogg+ d[n until ! fir/ ^w 8laugh0 on ! read+ c>d1 9 l9e #ge,m1 is p]fectly cle>1 ?is be+ slightly small] ?an ! av]age newspap] type4 #ad?--,aft] completion ( exam9ation = ea* eye sep>ately1 !n ) bo? eyes direct pati5t's att5tion to ^w 8laugh40 ,move read+ c>d 9 or out a few in*es ei!r side ( #ad in* m>k4 ,?is w det]m9e any possibility ( an ov]-correction4 ,!n record prescription j z ,ski-optomet] indicates4 ,= a detail$ description ( above1 z well z = objective te/+ ) ! ,ski-optomet]1 read *apt] ?ree4 ,,*apt] ,,vi ,,muscul> ,,imbalance ,! purpose ( ! pres5t *apt] is to acqua9t ! refractioni/ ) ! op]ation ( ! ,ski-optomet] z 8a sci5tific in/rum5t = muscle te/+0--! subject be+ treat$ z briefly & compreh5sively z is practicable4 ,z ! read] progresses 9 ! subject ( muscul> anomalies1 he may c>ry 8 "w to z high a plane z desir$1 increas+ 8 pr(essional usefulness to an enviable degree4 ,?r\gh ! use ( ! ,ski-optomet]1 muscle te/+ may be accurately accompli%$ 9 less "t ?an a description ( ! op]ation requires4 ,fur!rmore1 t$i\s exam9ations may be :olly ov]come ?r\gh ! discont9uance ( ! consecutive transf]5ce ( ! v>i\s degrees ( prisms f ! trial-case4 ,9 fact1 ! latt] me?od has long be5 q obsolete1 ow+ to ! possibility ( inaccuracy4 ,! muscle action ( ! eye is usually quick] ?an ! result s\ght ?r\gh ! use ( trial-case prisms2 h5ce muscle te/+ ) ! ,ski-optomet] is accompli%$ ) f> great] rapidity & accuracy1 ?us mak+ ! in/rum5t an invaluable appliance 9 e exam9ation4 ,,! ,,action ,,( ,,prisms ,/ud5ts 9 refraction--& "o may /ill be a /ud5t aft] ye>s ( refract+--are sometimes puzzl$ z to j :at a prism does :5 plac$ be=e an eye4 ,!y ref] to e available volume & are (t5 confus$ betwe5 ductions & phorias1 f9ally dropp+ ! subject z an unsolvable problem4 ,9 view ( ?is fact1 x is sugge/$ t ! refractioni/ %\ld read ! pres5t volume ) ! actual in/rum5t be=e him4 ,be=e proce$+1 "o %\ld fir/ und]/& ! effect ( a prism & :at x accompli%es4 ,to det]m9e ?is1 close "o eye1 look+ at "s small1 fix$ object2 at ! same "t1 hold a t5 degree prism base 9 be=e ! op5 eye1 not+ displacem5t ( ! object4 ,?is w cle>ly %[ t ! eye beh9d ! prism turns t[>d ! prism apex4 ,to c>ry ! exp]im5t fur!r1 ! foll[+ te/ may be employ$ on a pati5t4 ,cov]+ "o eye1 direct 8 att5tion to a fix$ object1 plac+ ! t5 degree prism be=e ! eye1 b f> en\gh away to see ! pati5t's eye beh9d x4 ,z ! prism is br\ght 9 to ! l9e ( vision1 x w be se5 t ! eye turns t[>ds ! apex ( ! prism4 ,:5 ! prism is remov$1 ! eye returns to its normal position4 ,simil> exp]im5ts enable ! refractioni/ to make ! mo/ practical use ( treat+ phorias & ductions1 z well z to compreh5d all o!r te*nical "w4 ,illu/ration3 ,fig4 #ac--;,an important "p ( ! equipm5t = muscul> "w4 ,,! ,,phoromet] ,z previ\sly /at$1 x is practically impossible to accurately diagnose a case ( muscul> imbalance ) trial-case prisms4 ,= ?is reason ! phoromet] =ms an important "p ( ! equipm5t = muscle te/+ 9 ! ,ski-optomet]1 hav+ prov5 bo? rapid & accurate4 ,x consi/s ( two five-degree prisms ) bases opposite1 ea* reflect+ an object t[>d ! apex or ?9 edge4 ,! pati5t ^: att5tion is direct$ to ! usual muscle-te/+ spot ( light1 w see two spots4 ,aside f ! in/rum5t itself1 & 9 fur!r explanation ( ! phoromet]'s pr9ciple & con/ruction1 :5 two five-degree prisms are plac$ toge!r s t _! bases are directly opposite1 !y naturally neutralize2 :5 _! bases are toge!r1 _! /r5g? is d\bl$4 ,?us :ile ! prisms ( ! phoromet] are rotat+1 !y give prism values f plano to t5 degrees1 ! same be+ indicat$ by ! po9t] on ! phoromet]'s scale ( measurem5ts4 ,z a guide 9 d>k-room te/+1 x %\ld be not$ t ! h&le ( ! phoromet] 9 a v]tical position is an indication t ! v]tical muscles are be+ te/$2 if horizontal1 ! horizontal muscles are und]go+ ! te/4 ,,! ,,maddox ,,rod ,! ,maddox rod 7,fig4 #ad7 consi/s ( a numb] ( r$ or :ite rods1 :i* cause a correspond+ color$ /reak to be se5 by ! pati5t4 ,?is rod is plac$ mo/ conv5i5tly on ! in/rum5t1 be+ provid$ ) indep5d5t /ops = accurately sett+ ! rods at #ij or #ahj degree positions4 ,! ,maddox rod has prov5 ( valuable assi/ance 9 detect+ muscul> defects1 p>ticul>ly :5 us$ 9 conjunction ) ! phoromet]4 ,?us employ$1 x enables ! pati5t to det]m9e :5 ! /reak se5 ) "o eye crosses ?r\gh ! muscle-te/+ spot-light obs]vable by ! o!r eye1 z h]eaft] describ$4 ,illu/ration3 ,fig4 #ad--,! ,maddox ,rod1 a valuable aid 9 mak+ muscul> te/s4 ,,proc$ure ,,= ,,mak+ ,,! ,,muscle ,,te/ ,! ,ski-optomet] %\ld be equipp$ ) two ,maddox rods1 "o r$ & "o :ite4 ,_! comb9$ use is ( ! utmo/ importance s9ce !y assi/ 9 accurately det]m9+ cyclophoria & its degree ( tortion z designat$ on ! degree scale1 & fully describ$ 9 a lat] *apt]4 ,:5 ! ,maddox rods are plac$ 9 a v]tical position1 x is an indication t ! v]tical muscles are be+ te/$2 :5 plac$ horizontally1 ! horizontal muscles are be+ te/$4 ,x %\ld be p>ticul>ly not$ t ! /reaks ( light obs]vable ?r\gh ! ,maddox rods always appe> at "r angles to ! position 9 :i* !y lie4 ,! ,ski-optomet] %\ld be plac$ 9 a com=table position be=e ! pati5t's face ) ! br[-re/ & pupill>y di/ance adju/$ to _! respective requirem5ts4 ,! in/rum5t %\ld be levell$ s t ! bubble ( ! _s level lies ev5ly betwe5 its two l9es1 ?us insur+ horizontal balance4 ,! muscle te/ light %\ld be employ$ at an approximate di/ance ( tw5ty feet on a plane ) ! pati5t's head4 ,be/ results 9 muscle te/+ are secur$ ?r\gh ! use ( ! ,woolf oph?almic bracket1 ) iris diaphragm *imney & a specially adapt$ conc5trat$ filam5t electric lamp 7,fig4 #i74 ,?is gives a brilliant illum9ation :i* is p>ticul>ly ess5tial4 ,! te/ = error ( refraction %\ld be made 9 ! usual mann]1 us+ ! sph]ical & cyl9drical l5ses conta9$ 9 ! ,ski-optomet]1 ?us obviat+ ! transf]5ce ( trial-case l5ses & ! use ( a cumb]some trial-frame4 ,! "t-sav+ ?us effect$ enables ! refractioni/ to include a muscle te/ 9 e exam9ation & )\t tir+ ! pati5t--a consid]ation ( ! utmo/ importance4 ,,b9ocul> ,,& ,,monocul> ,,te/ ,! te/ = muscul> imbalance may be divid$ 9 two p>ts4 ,fir/1 b9ocul> te/1 or comb9$ muscle te/ ( ! two eyes2 second1 monocul> te/1 or muscle te/ ( ea* eye sep>ately4 ,! latt] does n signify ! %utt+ out ( vision or clos+ (f ( ei!r eye1 s9ce muscul> imbalance c only be det]m9$ :5 bo? eyes are op54 ,^! two te/s are fully expla9$ 9 ! foll[+ *apt]4 ,,*apt] ,,vii ,,! ,,b9ocul> ,,muscle ,,te/ ,,made ,,) ,,! ,,maddox ,,rod ,,& ,,phoromet] ,direct+ ! pati5t's att5tion to ! usual muscle te/+ spot ( light1 ! r$ ,maddox rod %\ld be plac$ 9 op]ative position be=e ! eye1 ) ! s+le :ite l9e or indicator on r$ z]o 7,fig4 #ae74 ,! rods n[ lie 9 a v]tical position4 ,illu/ration3 ,fig4 #ae--,! ,maddox rods plac$ v]tically d5ote te/ = "r or left hyp]phoria1 caus+ a horizontal /reak to be se5 by pati5t4 ,! po9t] ( ! phoromet] %\ld likewise be set on ! neutral l9e ( ! r$ scale1 caus+ ! h&le to po9t upw>d 7,fig4 #af74 ,a di/ance po9t ( light & a r$ /reak lay+ 9 a horizontal position %\ld n[ be se5 by ! pati5t4 ,illu/ration3 ,fig4 #af--,! phoromet] h&le plac$ v]tically1 d5otes v]tical muscles are und]go+ te/ = "r or left hyp]phoria--z indicat$ by 8,r4 ,h40 or 8,l4 ,h40 ,in/ead ( memoriz+ a va/ numb] ( rules ess5tial :]e trial case prisms are employ$ = te/+ ocul> muscles1 ! po9t] ( ! phoromet] indicates n only ! degree on ! r$ scale1 b ! pres5ce ( "r hyp]phoria 7,r4 ,h47 or left hyp]phoria 7,l4 ,h474 ,illu/ration3 ,fig4 #ag--,! horizontal /reak caus$ by ,maddox rod bisect+ muscle te/+ spot-light = v]tical imbalance1 z pati5t %\ld see x4 ,assum+ t ! pati5t f9ds t ! /reak cuts ?r\gh ! po9t ( light1 ! refractioni/ in/antly notes ! abs5ce ( hyp]phoria4 ,%\ld ! po9t ( light & ! r$ /reak n bisect1 prism p[] mu/ be add$ by rotat+ ! phoromet]'s h&le to a position t w cause ! /reak to cut ?r\gh ! light 7,fig4 #ag74 ,:ile te/+ = hyp]phoria1 ! r$ scale %\ld alone be employ$1 ! :ite scale be+ totally ignor$4 ,illu/ration3 ,fig4 #ah--,! ,maddox rods plac$ horizontally te/ esophoria or exophoria1 caus+ a v]tical /reak to be se5 by ! pati5t4 ,,esophoria ,,& ,,exophoria ,! next /ep is to set ! :ite l9es ( ! r$ ,maddox rod ei!r at :ite z]o1 or #ahj l9e1 ) ! rods 9 a horizontal position 7,fig4 #ah7 & ! phoromet] on ! :ite neutral l9e1 ) h&le horizontal 7,fig4 #ai71 ?us mak+ ! te/ = esophoria or exophoria1 te*nically kn[n z lat]al deviations4 ,! r$ /reak w n[ be se5 9 a v]tical position4 ,%\ld x bisect ! spot ( light1 x w\ld %[ t no lat]al imbalance exi/s4 ,%\ld x n bisect1 ! exi/5ce ( ei!r esophoria or exophoria is prov51 necessitat+ ! turn+ ( ! phoromet] h&le4 ,%\ld ! refractioni/ rotate ! h&le 9 a direction oppos+ t ( ! exi/+ imbalance1 ! light w be tak5 fur!r away f ! /reak1 indicat+ t ! rotation ( ! prisms %\ld be rev]s$4 ,illu/ration3 ,fig4 #ai--,! phoromet] h&le plac$ horizontally d5otes horizontal muscles are und]go+ te/ = esophoria or exophoria indicat$ by 8,es40 or 8,ex40 ,at ! po9t ( bisection 7,fig4 #bj71 ! phoromet] w indicate on ! :ite scale :e!r ! case is esophoria or exophoria & to :at am\nt4 ,9 te/+ esophoria 7,,es7 or exophoria 7,,ex71 ! :ite scale is alone employ$1 no att5tion be+ giv5 to ! r$ scale4 ,illu/ration3 ,fig4 #bj--,! v]tical /reak bisect+ muscle te/+ spot-light = horizontal imbalance1 z pati5t %\ld see x4 ,,mak+ ,,muscle ,,te/ ,,be=e ,,& ,,aft] ,,optical ,,correction ,x is consid]$ be/ to make ! b9ocul> te/ be=e regul> refraction is made1 mak+ note ( ! f9d+s2 & aga9 repeat+ ! te/ aft] ! full optical correction has be5 plac$ be=e ! pati5t's eye4 ,?is enables ! refractioni/ to def9itely det]m9e :e!r ! correction has b5efit$ or aggravat$ ! muscles4 ,fur!rmore1 by mak+ ! muscle te/ be=e & aft] ! optical correction1 a />t+ po9t 9 an exam9ation is frequ5tly atta9$4 ,= example1 :]e ! phoromet] indicates esophoria x is usually associat$ ) hyp]opia1 :]eas exophoria is usually associat$ ) myopia1 ?us s]v+ z a clue = ! optical correction4 ,assum+ = example t ! b9ocul> muscle te/ %[s six degrees ( esophoria )\t ! optical correction1 & ) x b f\r degrees1 x is readily se5 t ! imbalance has be5 b5efit$ by ! optical correction4 ,"u su* conditions x is safe to believe t ! optical correction w cont9ue to b5efit z ! pati5t advances 9 ye>s1 t5d+ to ov]come muscul> defect4 ,,:5 ,,to ,,consid] ,,correction ,,( ,,muscul> ,,imbalance ,9 correct+ an imbalance1 x is also a good plan to adh]e to ! foll[+ rule3 ,9 case ( hyp]phoria1 ei!r "r or left1 consid] = fur!r correction only ^? cases t %[ "o degree or m4 ,9 exophoria1 ^? %[+ ?ree degrees or m4 ,9 esophoria1 correct ^? %[+ five degrees or m1 except 9 *ildr51 :]e correction %\ld be made 9 cases %[+ an excess ( #c ( esophoria4 ,^! rules are naturally subject to v>iation accord+ to ! pati5t's refraction & age1 b !y are g5]ally accept$ z safe4 ,,f\r ,,me?ods ,,= ,,correction ,,( ,,muscul> ,,imbalance ,!re are f\r di/9ct me?ods = correct+ muscul> imbalance1 ea* ( :i* %\ld be c>ri$ out 9 ! foll[+ r\t9e3 #a4 ,optical correction made ) sph]es or cyl9d]s1 or a comb9ation ( bo?4 #b4 ,muscul> ex]cis+ or 8ocul> gymna/ics40 ,?is is accompli%$ on ! same pr9ciple z ! employm5t ( o!r =ms ( ex]cises1 or cali/h5ics4 #c4 ,! use ( ,prisms3 ,:5 ! second me?od fails1 prisms are suppli$1 ) base ( prism be=e ! weak muscle1 = re/ only4 #d4 ,op]ation3 ,if ! above ?ree me?ods1 z outl9$ 9 ! foll[+ *apt]s1 h be5 c>efully inve/igat$1 no?+ rema9s b a tetonomy or advancem5t1 or o!r op]ative means = relief & satisfaction to ! pati5t4 ,,! ,,rot>y ,,prism ,! rot>y prism ( ! ,ski-optomet]1 7,fig4 #ba7 consi/s ( a prism unit1 hav+ a total equival5t ( ?irty degrees4 ,x is compos$ ( two fifte5-degree prisms1 back to back1 s t ! turn ( its p9ion or h&le causes ea* ( its l5ses to revolve1 "o on ! o!r4 ,:5 its bases are opposite1 !y neutralize2 :5 directly toge!r1 !y give a total value ( ?irty degrees4 ,:ile revolv+ f z]o to maximum /r5g?1 !y give prism values :i* are indicat$ on ! scale ( measurem5ts1 ! r$ l9e d5ot+ ! total prism equival5t4 ,illu/ration3 ,fig4 #ba--,turn+ rot>y prism's p9ion$ h&le gives prism value f z]o to #cj z indicat$ by prism's r$ l9e indicator4 ,x is obvi\sly ess5tial to "k :]e ! base ( ! rot>y prism is locat$4 ,!re=e if prism 9 or out is desir$1 ! z]o graduations %\ld be plac$ v]tically & ! r$ l9e or indicator set at ! upp] z]o 7,fig4 #ba74 ,a rotation inw>d to #aj w\ld give a prism equival5t ( t5 degrees1 base 94 ,a rotation f z]o to #aj outw>d w\ld give a prism equival5t ( t5 degrees1 base out1 etc4 ,) z]o graduations horizontal & ! r$ l9e or indicator set !re)1 a rotation upw>d to t5 on ! scale w\ld give a prism equival5t ( t5 degrees1 base up4 ,a rotation f z]o d[nw>d to #aj w\ld give a prism equival5t ( t5 degrees1 base d[n4 ,an und]/&+ ( ! =ego+ w %[ t a rotation ( ! r$ l9e1 or indicator1 w give prism value f z]o to #cj1 ) base up1 d[n1 9 or out4 ,,use ,,( ,,! ,,rot>y ,,prism ,,9 ,,b9ocul> ,,muscle ,,te/s ,%\ld a case be "o ( esophoria1 exce$+ ! t5 degree range ( ! phoromet]1 ! rot>y prism %\ld be br\ght into op]ative position ) cyph] 7#j7 graduations v]tical 7,fig4 #ba71 :ile ! r$ l9e or indicator %\ld be set at #aj on ! out] or temporal scale4 ,! phoromet]'s indicator %\ld aga9 be set on ! c5t] or neutral l9e on ! :ite scale4 ,! rot>y prism w !n add t5 degrees to ! esophoria read+ indicat$ on ! phoromet]4 ,%\ld ! case be "o ( exophoria1 exce$+ t5 degrees1 ! indicator %\ld be set at t5 degrees ^u ! inn] or nasal scale & ! indicator ( ! phoromet] %\ld !n be set at ! :ite c5t] or neutral l9e1 z 9 ! previ\s te/4 ,%\ld prism p[] ev] be requir$ to supplem5t ! phoromet] 9 hyp]phoria1 ! rot>y prism %\ld be employ$ ) z]o graduations horizontal1 & ! r$ l9e or indicator set at t5 degrees on upp] or l[] scale1 z requir$4 ,,*apt] ,,viii ,,! ,,monocul> ,,duction ,,muscle ,,te/ ,,made ,,) ,,bo? ,,rot>y ,,prisms ,:ile ! previ\sly describ$ b9ocul> muscle te/ made ) ! phoromet] & ,maddox rod1 only det]m9es ! exi/5ce & am\nt ( esophoria1 exophoria1 & hyp]phoria1 nei!r ! faulty nor ! deviat+ muscle is locat$1 h5ce a monocul> muscle te/ is ess5tial 9 ord] to det]m9e :e!r ! muscles ( ! "r or left eye are faulty4 ,fur!rmore1 an imbalance may possibly be due to ei!r a faulty muscul> poise1 or lack ( n]ve =ce 9 "o or bo? eyes4 ,a 8duction te/0 %\ld accord+ly be made ( ea* muscle ( ea* eye sep>ately1 foll[$ by a comp>ison ( ! muscul> pull ( bo? eyes collectively4 ,^! te/s are commonly t]m$ adduction1 abduction1 sup]duction & subduction1 & are def9$ 9 ! ord] nam$4 ,!y include te/s ( ! v]tical & horizontal muscles ( ea* eye1 made individually by means ( ! rot>y prisms1 ea* be+ plac$ be=e ! eye und]go+ ! te/4 ,,locat+ ,,! ,,faulty ,,muscle ,! phoromet] & ! ,maddox rod %\ld be remov$ f op]ative position1 discont9u+ ! use ( ! muscle-te/+ spot-light1 employ$ 9 ! previ\sly describ$ b9ocul> te/4 ,! optical correction1 if "o is requir$1 %\ld be left 9 place1 :ile ! pati5t's att5tion %\ld be direct$1 ) bo? eyes op51 to ! l>ge/ lett] on ! di/ant te/ *>t2 or if pref]able1 ! ,greek cross 9 ! ,woolf oph?almic1 *imney may be us$4 ,ei!r "o1 h[ev]1 %\ld be locat$ on a plane ) ! pati5t's head4 ,z a guide = ! op]ator1 x might be well to rememb] t :5 ! h&le ( ! rot>y prism is 9 a horizontal position1 ! lat]al or horizontal muscles are be+ te/$4 ,on ! o!r h&1 :5 ! h&le is 9 a v]tical position1 ! v]tical muscles are und]go+ ! te/4 ,,adduction ,adduction1 or relative conv]g5ce1 is ! p[] ( ! int]nal muscles to turn ! eyes inw>d2 prism p[] base out & apex 91 is employ$4 ,illu/ration3 ,fig4 #bb--,to te/ adduction1 base out is requir$4 ,rot>y prism's l9e or indicator %\ld be rotat$ f z]o outw>dly4 ,to te/ abduction1 base 9 is requir$4 ,indicator %\ld be rotat$ inw>dly f z]o4 ,to te/ adduction ( ! pati5t's "r eye1 ! rot>y prism %\ld be plac$ 9 position be=e ! "r eye1 ! r$ l9e or prism indicator be+ regi/]$ at z]o ^u ! prism upp] scale4 ,! two cyph]s 7#j7 %\ld be plac$ 9 a v]tical position ) ! h&le po9t$ horizontally 7,fig4 #ba74 ,! rot>y prism %\ld !n be rotat$ s t its r$ l9e or indicator is rotat$ outw>d f z]o until ! l>ge lett]--pref]ably ! l>ge/ lett]1 :i* is usually 8,e0--on ! di/ance te/-type or ! ,greek cross previ\sly ref]r$ to1 fir/ appe>s to d\ble 9 ! horizontal plane4 ,! read+ on ! scale ( measurem5ts %\ld accord+ly be not$4 ,?is te/ %\ld be repeat$ sev]al times1 con/antly /riv+ = ! highe/ prism p[] t ! pati5t w accept )\t produc+ diplopia4 ,! prism equival5t ?us obta9$ w indicate ! "r adduction & %\ld be s record$1 z designat$ 9 ,fig4 #bd4 ,! am\nt ( adduction ranges f #f to #bh1 prism diopt]s1 ! normal av]age be+ #bd4 ,,abduction ,abduction is ! relative p[] ( ! ext]nal muscles to turn ! eyes outw>d4 ,prism p[] base 9 & apex out is employ$4 ,to det]m9e abduction1 or ! am\nt ( div]g5ce ( ! ext]nal rectus muscle ( ! "r eye1 prism p[] ) base 9 or t[>d ! nasal side %\ld be employ$4 ,! rot>y prism w !re=e rema9 9 ! same relative position z 9 mak+ ! adduction te/ 7,fig4 #bb71 ) ! two cyph]s 7#j7 or z]o graduations v]tical1 b ! indicator or r$ l9e %\ld be rotat$ inw>d f z]o1 or t[>ds ! pati5t's nose4 ,) ! pati5t's att5tion aga9 direct$ to ! l>ge lett] 8,e10 or ! ,greek cross1 ?is inw>d rotation %\ld be cont9u$ until diplopia or d\ble vision occurs4 ,l ! =m]1 ?is te/ %\ld be repeat$ sev]al times1 ! refractioni/ cont9u+ to /rive = ! highe/ prism p[] :i* ! eye w accept4 ,?is w indicate abduction ( ! "r eye & %\ld be s record$ z designat$ 9 ,fig4 #bd4 ,! am\nt ( abduction ranges f #c to #aj prism diopt]s4 ,! normal av]age is #h4 ,! ratio ( adduction to abduction is normally rat$ at ab\t ?ree to "o4 ,9 o!r words1 x is conc$$ t ! p[] ( ! eye to conv]ge is normally ?ree times z great z its p[] to div]ge1 ! usual measurem5ts be+ eight to tw5ty-f\r respectively4 ,:ile applicable 9 mo/ in/ances1 ?is may v>y 9 diff]5t cases4 ,,sup]duction ,sup]duction1 sometimes t]m$ sursumduction1 is ! relative p[] ( ! sup]ior recti to turn ! eyes upw>d4 ,prism p[] base d[n & apex up is employ$4 ,to te/ sup]duction1 ! rot>y prism %\ld be plac$ 9 position ) ! two cyph]s ly+ horizontally1 ) ! h&le po9t$ v]tically 7,fig4 #bc74 ,! pati5t's att5tion %\ld aga9 be direct$ to ! l>ge lett] 8,e01 & ! indicator or r$ l9e %\ld be rotat$ d[nw>d f z]o4 ,! highe/ prism p[] t ! pati5t w accept be=e ! object appe>s to d\ble 9 ! v]tical plane w indicate ! degree ( "r sup]duction4 ,?is %\ld be record$ accord+ly4 ,conditions ( ?is k9d d n usually exce$ two or ?ree degrees4 ,! te/1 h[ev]1 %\ld be repeat$ sev]al times be=e ! f9al result is record$1 z indicat$ 9 ,fig4 #bd4 ,! am\nt ( sup]duction ranges f #a to #d prism diopt]s4 ,! normal av]age is #b4 ,illu/ration3 ,fig4 #bc--,to te/ sup]duction1 base d[n is requir$4 ,rot>y prism's l9e or indicator %\ld be rotat$ d[nw>d f z]o4 ,to te/ subduction1 base up is requir$4 ,indicator %\ld be rotat$ upw>d f z]o4 ,,subduction ,subduction1 sometimes t]m$ infraduction or deorsumduction1 is ! relative p[] ( ! inf]ior recti to turn ! eyes d[nw>d4 ,prism p[] base up & apex d[n is employ$4 ,to te/ subduction1 ! rot>y prism %\ld be op]at$ ) z]o graduations plac$ horizontally1 z 9 ! sup]duction te/ 7,fig4 #bc71 b ! indicator %\ld be sl[ly rotat$ 9 ! rev]se direction1 or upw>d f z]o4 ,) ! pati5t's att5tion aga9 direct$ to ! l>ge lett] 8,e10 or ! ,greek cross1 ! /ronge/ degree prism ?us secur$ )\t diplopia w indicate ! "r subduction4 ,! am\nt ( subduction ranges f #a to #d prism diopt]s4 ,! normal av]age is #b4 ,any diff]5ce betwe5 sup]duction & subduction1 usually d5ot+ ! exi/5ce ( hyp]phoria1 %\ld be giv5 c>eful consid]ation4 ,,proc$ure ,,= ,,monocul> ,,muscle ,,te/+ ,z previ\sly expla9$1 aft] a duction te/ ( ea* ( ! f\r muscles ( ! "r eye1 ! rot>y prism be=e t eye %\ld be plac$ out ( position & ! proc$ure = adduction1 abduction1 sup]duction & subduction repeat$ by means ( ! rot>y prism be=e ! left eye4 ,9 case ( an exi/+ imbalance1 aft] te/+ ! muscle ( bo? "r & left eyes1 ! refractioni/ c quickly det]m9e :i* muscle or muscles may be lack+ 9 /r5g? 7,fig4 #bd74 ,9 practically e in/ance muscle ex]cises or correct+ prisms may !n be prescrib$ ) def9ite k ( requirem5ts1 z fur!r describ$ 9 ! foll[+ p>agraphs4 ,a b9ocul> muscle te/ made ) ! phoromet]1 ,maddox rod & di/ant muscle-te/+ po9t ( light might quickly indicate six degrees ( exophoria1 bo? be=e & aft] ! optical correction is made4 ,:ile ?is w\ld d\btless be ! correct am\nt ( ! manife/ imbalance1 x w\ld be a difficult matt] to asc]ta9 :i* muscles caus$ ! di/urbance4 ,to det]m9e ?is important "q1 ! monocul> or duction te/ %\ld be inv>iably employ$4 ,,diagnos+ ,a ,,specific ,,muscle ,,case ,assum+1 = example1 a specific case :]e six degrees ( exophoria 0 det]m9$ 9 ! b9ocul> te/ t ! muscle f9d+s 9 ! duction te/ %[ "r adduction ( tw5ty-f\r degrees1 ) an accompany+ abduction ( eight degrees2 likewise a sup]duction & subduction ( two degrees = ea* eye4 ,) ! aid ( a *>t or diagram--:i* %\ld be made 9 e case--a comp>ison ( ^! figures w\ld indicate an exophoria ( approximately six degrees1 ) a correspond+ weak left int]nus 7,fig4 #bd74 ,?is n only %[s ! muscle pull ( ea* eye individually1 b a comp>ison ( ! two eyes z indicat$ by ! dott$ l9es4 ,?us ! relation%ip ( ! two eyes1 & _! correspond+ muscles is quickly indicat$4 ,illu/ration3 ,fig4 #bd--;,duction *>t %\ld be made 9 e case4 ,above readily %[s exi/5ce ( muscul> imbalance & proves subduction & sup]duction = bo? eyes are equal2 o!rwise hyp]phoria w\ld be disclos$4 ,also note abduction = bo? "r & left eye are equal1 o!rwise esophoria w\ld be disclos$4 ,also note adduction = "r eye is #bd :ile left is b #ah1 prov+ a case ( #f ( exophoria ) a left weak int]nus4 ,a glance at ! above diagram discloses ! foll[+ ?ree important facts1 all ( :i* %\ld be kn[n to ! refractioni/ be=e a s+le ?\ght c be devot$ to ! correct+ ( ! case3 #a4 #f exophoria is ! am\nt ( ! insuffici5cy4 #b4 #ah adduction 7:i* %\ld be #bd74 #c4 ,left weak int]nus4 ,z previ\sly /at$1 ! p[] to conv]ge is normally rat$ #c to #a1 or #h to #bd1 z %[n above1 :ile ! p[] ( ! eye to look upw>d1 is equal to ! p[] to look d[nw>d4 ,! diagram accord+ly proves t ! muscles ( ! "r eye are 9 p]fect balance1 hav+ equal muscul> en]gy4 ,a comp>ison ( ! left eye %[s adduction ( #ah degrees ) an abduction ( #h degrees1 prov+ a lat]al insuffici5cy because ! ratio is less ?an #c to #a2 & ! muscles ( ! left eye are at fault4 ,! p[] ( #b degrees sup]duction & #b degrees subduction1 proves t no weakness exi/s 9 ! v]tical muscles4 ,aft] mak+ ! duction te/ = ea* eye individually1 a comp>ison ( bo? eyes 9 relation%ip to ea* o!r may be m readily det]m9$ by foll[+ ! dott$ l9es 7,fig4 #bd74 ,z previ\sly /at$1 x is ! inability ( ! two eyes to "w toge!r t causes ! imbalance1 s t if bo? eyes 7 normal1 ! adduction1 abduction1 sup]duction & subduction ( ! two eyes w\ld agree4 ,! duction *>t 7,fig4 #bd47 also %[s t ! correspond+ muscles ( ea* eye agree--) ! exception ( ! adduction ( ! "r eye & ! left eye4 ,?is proves t ! left int]nus is weak1 measur+ only #ah degrees in/ead ( #bd degrees2 x fur!r proves ! #f degrees ( exophoria 9 ! monocul> te/1 z 0 quickly & m readily det]m9$ 9 ! b9ocul> te/4 ,likewise1 9 cases ( esophoria1 hyp]phoria1 or cataphoria1 ! mak+ ( def9ite muscle measurem5ts indep5d5tly ?r\gh ! prescrib$ me?od w\ld %[ ?r\gh ! m]e/ glance at a simil> diagram :i* muscle or muscles 7 relatively out ( balance4 ,het]phoria ( almo/ any type1 or t5d5cies o!r ?an normal1 may be fully inve/igat$ by mak+ a ?or\gh & sep>ate te/ ( ea* muscle4 ,:]e an imbalance exi/s1 a rapid te/ may be employ$ to di/+ui% a pseudo or false condition f a true condition4 ,?is is accompli%$ by fir/ plac+ ! two ,maddox rods 7bo? ! r$ & :ite7 s t ! rods lie 9 a v]tical position4 ,if ! two l9es fuse1 we h det]m9$ ! exi/5ce ( a false condition caus$ by a possible error ( refraction or n]ve /ra94 ,if ! l9es sep>ate1 we h det]m9$ a true muscul> condition1 & !n only %\ld ! second me?od ( muscul> treatm5t foll[4 ,illu/ration3 ,same z ,model #bae b ,automatic ,cyl9d] ,arrangem5t omitt$4 ,,ski-,,optomet] ,,model #bje ,embody+ ,sph]ical ,l5ses ,comb9$ ) ,appliances = ,te/+ & ,correct+ ,muscul> ,imbalance4 ,,*apt] ,,ix ,,fir/ ,,me?od ,,( ,,treatm5t ,,optical ,,correction ,! m]e det]m9ation ( ! degree ( an imbalance1 or ev5 ! diagnosis ( a pati5t's tr\ble1 is n suffici5t4 ,if relief is to be secur$1 some?+ m mu/ be accompli%$4 ,z previ\sly /at$1 muscul> imbalance may be correct$ ?r\gh "o ( ! f\r foll[+ rules or me?ods1 ea* expla9$ 9 _! relative ord]3 #a--,optical ,correction #b--,muscul> ,ex]cise #c--,use ( ,prism ,l5ses #d--,op]ative ,me?ods ,,esophoria ,to correct a case ( muscul> imbalance1 :]e six degrees ( esophoria has be5 det]m9$1 ! fir/ rule ( mak+ ! te/ = optical correction ) ! ,ski-optomet]'s sph]ical & cyl9drical l5ses1 w\ld be 9 ! l9e ( r\t9e4 ,! b9ocul> te/ made ) ! phoromet] & comb9$ use ( ! r$ ,maddox rod w\ld h det]m9$ ! six degrees ( esophoria4 ,! reason = mak+ ! b9ocul> muscle te/ be=e & aft] ! optical correction is because an imbalance is (t5 aggravat$ or b5efit$ by ! correct+ l5ses4 ,! optical correction frequ5tly elim9ates ! ne$ = fur!r muscul> treatm5t4 ,= example1 we w assume t ! optical correction t5ds to decrease ! degree ( esophoria f six degrees to f\r degrees4 ,accord+ to ! previ\sly m5tion$ rule = correct+ cases exce$+ "o degree 9 hyp]phoria1 ?ree degrees 9 exophoria & five degrees 9 esophoria1 ! condition w\ld indicate t ( be+ 8left alone40 ,j :at is tak+ place %\ld be fully und]/ood--its cause z well z its effect4 ,illu/ration3 ,fig4 #be--;,comp>ative diagram %[+ h[ a dec5t]$ l5s be=e a c5t]$ eye has ! same effect z a c5t]$ l5s be=e a dec5t]$ eye4 ,:5 n o!rwise specifi$1 accurately c5t]$ l5ses are ( prim>y importance4 ,! pupil ( ! eye %\ld be directly beh9d ! c5t] ( ea* l5s 7,fig4 #be74 ,figure 8,a0 ( ! latt] sket* illu/rates a p]fectly c5t]$ l5s--its c5t] indicat$ by a cross1 ! circle repres5t+ an eye directly beh9d x4 ,figure 8,b0 illu/rates a p]fectly c5t]$ pupil beh9d a prism1 ) its c5t] designat$ by a cross4 ,to asc]ta9 h[ ! c5t]$ sph]ical l5s takes ! place ( a prism1 ,figure 8,c0 %\ld be comp>$ ) ,figure 8,b02 ?is w %[ t ! eye is dec5t]$1 :ile ! l5s is c5t]$4 ,a fur!r comp>ison w prove t ! results 9 ,figures 8,b0 & 8,c0 are id5tical1 ! correct+ l5ses hav+ practically ! same effect ?r\gh ! dec5tration ( ! eye z if a prism 7 prescrib$1 nature supply+ its own dec5tration4 ,,treatm5t ,,= ,,correct+ ,,esophoria ,,9 ,,*ildr5 ,9 case ( esophoria1 reg>dless ( am\nt1 slightly increas$ sph]ical p[] is frequ5tly prescrib$ = *ildr54 ,?is w naturally blur or fog ! pati5t's vision1 b 9 _! ef=t to ov]come ! blur1 accommodation is relax$1 usually t5d+ to correct ! muscul> defect4 ,9 su* cases1 z a rule1 a qu>t] diopt] increas$ sph]ical /r5g? may frequ5tly be add$ = ea* degree ( esophoria z det]m9$ be=e ! optical correction 0 made4 ,9 a case ( #f degrees ( esophoria1 ! refractioni/ may prescribe #a4ej diopt] sph]ical add$ to ! optical correction1 :i*1 let u assume1 is #a4jj sph4 -#a4jj cyl4 ax4 #ahj1 s t ! treatm5t glasses w\ld be #b4ej sph4 -#a4jj ax4 #ahj 7,see ,proc$ure on ,page #gd74 ,at ! end ( ea* ?ree mon?s' p]iod1 ! pati5t %\ld be reque/$ to return1 :5 ! b9ocul> & ! duction te/ %\ld aga9 be made1 comp>+ results ) ! "w previ\sly accompli%$4 ,an improvem5t t5d+ to build up ! left weak ext]nus w possibly p]mit ( a decrease ( ! excessive sph]ical p[]1 s t excessive sph]ical p[] is r$uc$ until completely remov$1 9 all probability ov]com+ ! muscul> defect4 ,esophoria is almo/ inv>iably a false condition & frequ5tly is outgr[n "u ?is treatm5t z ! *ild advances 9 ye>s4 ,on ! o!r h&1 esophoria unc>$ = 9 ! *ild may t5d to produce exophoria 9 ! adult4 ,,h[ ,,optical ,,correction ,,t5ds ,,to ,,decrease #f ,,esophoria ,,9 ,a ,,*ild ,illu/ration3 ,assume b9ocul> muscle te/ made be=e optical correction %[s #f ,esophoria4 #a4 ,sph4 -#a4 ,cyl4 ,ax4 #ahj4 ,next1 locate faulty muscle by mak+ a duction te/1 :i* %[s h[ abduction ( left eye is made to equal t ( "r eye1 *ange be+ made qu>t]ly ) treatm5t l5ses 9 accordance ) foll[+ rule4 ,note z abduction is increas$1 esophoria is r$uc$4 ,rule--prescribe a qu>t] diopt] increas$ sph]e = ea* degree ( imbalance or #j4be #f equals3 #a4ej add$ to optical correction4 #a_/a_/ai 7assum$ date7 prescrib$ treatm5t l5ses equal3 #b4ej -#a4 #ahj4 #d_/a_/ai 7#c mon?s lat]7 assum+ abduction has increas$ f #b to #c %[+ diff]5ce ( #e ,es4 or #j4be #e4 equals #a4be add$ to optical correction1 prescrib$ treatm5t l5ses equal3 #b4be -#a4 #ahj4 #g_/a_/ai 7#c mon?s lat]71 assum+ abduction has increas$ f #c to #d %[+ diff]5ce ( #d ,es4 or #j4be #d equals #a4jj :i* add$ to optical correction w\ld make prescrib$ treatm5t l5ses equal3 #b4jj -#a4 #ahj4 ,& s on1 e ?ree mon?s treatm5t l5ses are prescrib$ until bo? "r & left eye %[ #h ( abduction4 ,9 ?is way ! treatm5t l5ses are r$uc$ to orig9al correction ( #a4jj -#ajj #ahj4 ,?is w\ld h requir$ six *anges ( l5ses1 ?ree mon?s ap>t--?us consum+ #ah mon?s "t4 ,,*apt] ,x ,,second ,,me?od ,,( ,,treatm5t--,,muscul> ,,ex]cise ,,made ,,) ,,two ,,rot>y ,,prisms ,,& ,,r$ ,,maddox ,,rod ,,exophoria ,if a case is "o ( exophoria ( six degrees1 :]e ! second me?od ( treatm5t or muscul> ex]cise is 9 l9e ( r\t9e1 x is ess5tial to fir/ det]m9e ?r\gh a duction te/ & ! prep>ation ( ! diagram exactly :i* "o ( ! f\r muscles are faulty 7,fig4 #bd74 ,hav+ det]m9$1 ) ! aid ( ! diagram1 fir/1 ! exi/5ce ( #f degrees ( exophoria2 second1 #ah degrees ( adduction2 ?ird1 a weak left int]nus--! next proc$ure is to det]m9e :at degree ( prism w enable ! pati5t to obta9 s+le b9ocul> vision1 ) bo? eyes look+ 8/raight40 ,to det]m9e ?is1 place bo? ( ! ,ski-optomet]'s rot>y prisms 9 position ) ! h&le ( ea* po9t+ outw>d horizontally4 ,! r$ l9e or indicator ( ea* prism %\ld !n be plac$ at #cj ( ! out] scale 7,fig4 #bf74 ,! r$ ,maddox rod %\ld be horizontally position$ be=e ! eye1 ! :ite l9e on indicator po9t+ to #ahj ( ! scale 7,fig4 #bg74 ,! /r5g? ( ! rot>y prism be=e ! "r eye %\ld !reupon be r$uc$ by rotat+ ! prism indicator or r$ l9e t[>d ! upp] z]o 7#j7 to a po9t :]e ! pati5t fir/ sees ! r$ /reak--assum+ t ! r$ l9e appe>s at #db degrees1 t is #cj degrees be=e ! left eye & #ab degrees be=e ! "r4 ,illu/ration3 ,fig4 #bf 7,a & ,b7--,fir/ position ( rot>y prisms to det]m9e am\nt ( prism ex]cise to be employ$ = build+ up ! weak muscle4 ,! prism %\ld !n be /ill fur!r r$uc$ until ! v]tical /reak produc$ by ! ,maddox rod directly bisects ! muscle te/+ spot ( light4 ,assum+ t ?is po9t be ?irty-eight degrees1 :i* is f\r degrees less1 s+le b9ocul> vision is produc$4 ,illu/ration3 ,fig4 #bg--,position ( r$ ,maddox rod us$ 9 conjunction ) ,fig4 #bf = prism ex]cis+4 ,= example1 sixty degrees ( prism p[] 7! comb9$ p[] ( ! two rot>y prisms7 w usually cause complete di/ortion4 ,!re=e1 z outl9$ 9 ,figure #bh1 ! pati5t1 see+ only out ( ! "r eye1 w detect no?+ b a :ite light4 ,by gradually r$uc+ ! /r5g? ( ! prism be=e ! "r1 :i* is ! good eye1 ! pati5t w ev5tually see a r$ /reak (f to ! left4 ,a cont9u$ & gradual r$uction to a po9t :]e ! r$ /reak bisects ! :ite light1 w det]m9e h[ mu* prism p[] is requir$ = ! pati5t to obta9 s+le b9ocul> vision1 ?us e/abli%+ ! same image at ! same "t on ea* fovea or ret9a 7,fig4 #bj74 ,?is has taught ! pati5t to d t :i* he has nev] be=e accompli%$4 ,!re=e1 aft] hav+ be5 taught h[ to make ! two eyes "w 9 relation to ea* o!r1 ! natural t5d5cy !reaft] w be to /rive = ! same relation%ip ( vision ) bo? eyes4 ,! refractioni/ %\ld !n aim to r$uce ! excessive am\nt ( prism requir$ to give b9ocul> vision1 :i* c be accompli%$ by muscul> ex]cise4 ,x mu/ always be rememb]$ be=e ! refractioni/ is ready to employ ! muscul> ex]cise or second me?od1 t ! degree ( prism requir$ to give ! pati5t s+le b9ocul> vision mu/ be det]m9$ ) ! optical correction 9 place4 ,! ex]cise mu/ be practis$ daily 9 r\t9e1 a daily record be+ ess5tial4 ,,an ,,assum$ ,,case ,we w assume a case :]e #db degrees is requir$ to enable ! pati5t to fir/ see ! r$ /reak z produc$ by ! ,maddox rod to ! extreme left4 ,?r\gh a cont9u$ gradual r$uction ( #d degrees 7or to #ch degrees71 we next le>n t ! /reak 0 c>ri$ ov] until x bisect$ ! :ite spot ( light1 giv+ s+le b9ocul> vision & produc+ a position ( re/4 ,illu/ration3 ,fig4 #bh--,simplifi$ *>t %[+ ! prism action employ$ 9 develop+ a weak ocul> muscle ?r\gh alt]nat+ prism ex]cise4 ,ei!r side ( #ch 9 excess ( #d caus+ diplopia4 ,! pati5t has n[ e/abli%$ ! limitation ( ! ex]cise1 :i* is f\r degrees1 ?is limitation be+ det]m9$ by ! diff]5ce betwe5 ! po9t :]e ! /reak 0 fir/ se5 to ! extreme side & :]e x bisect$ ! spot4 ,! same am\nt ( f\r degrees %\ld !n be us$ = ! opposite side1 ?us r$uc+ ! prism /r5g? to #cd degrees4 ,?is aga9 produces diplopia1 because ( ! less] am\nt ( prism p[] employ$ to give s+le b9ocul> vision4 ,! refractioni/ %\ld !n return to #ch degrees1 :]e s+le b9ocul> vision _h orig9ally be5 det]m9$ 7,fig4 #bh71 alt]nat+ back to #db1 return+ to #ch1 ov] to #cd1 back to #ch1 & s on4 ,?is proc$ure %\ld be employ$ once a day j aft] meals = ab\t five m9utes1 & repeat$ t5 times1 con/antly /riv+ = a slight r$uction ( prism p[] f day to day4 ,,effect ,,( ,,muscul> ,,ex]cise ,?is muscul> treatm5t1 or con/ructive ex]cis+1 %\ld enable ! pati5t to ov]come 8 am\nt ( f\r degrees 9 ei!r direction 9 ab\t a week4 ,h5ce 9 ! case %[+ #ch degrees = s+le b9ocul> vision1 results may be look$ = 9 ab\t n9e weeks--f\r degrees divid$ into #ch degrees4 ,:ile ! pati5t is und]go+ ! treatm5t1 :i* is no?+ m ?an ! /r5g!n+ ( ! int]ni muscles or develop+ adduction1 x is natural to believe t ! am\nt ( imbalance is likewise be+ conqu]$4 ,?is1 h[ev]1 is readily det]m9$ f "t to "t by mak+ ! b9ocul> muscle te/ ) ! phoromet] & ,maddox rod1 z well z ! duction *>t te/ 7,fig4 #bd71 z previ\sly outl9$4 ,to fully appreciate ! effect ( ?is muscul> treatm5t1 ! read] ne$ only hold 8 head 9 a /ation>y position1 ca/+ 8 eyes sev]al times f ! extreme "r to ! extreme left1 n fail+ to note ! app>5t muscul> /ra94 ,on ! o!r h&1 ) ! aid ( ! ,ski-optomet]'s rotat+ prisms1 ! refractioni/ n only has complete control ( ! pati5t's muscles at all times1 b sci5tifically accompli%es muscul> ex]cise )\t any tiresome /ra91 ov]com+ all possible ex]tion4 ,aft] ! case 9 "q has be5 r$uc$ to #cj degrees1 hav+ no fur!r use = ! rot>y prism1 x may be remov$ f be=e ! "r eye & ! same ex]cis+ proc$ure cont9u$ z be=e ) ! rema9+ left side rot>y prism by r$uc+ its p[]1 until x is likewise d[n to z]o4 ,hav+ r$uc$ bo? prisms to z]o1 ea* prism %\ld aga9 be plac$ 9 position ) z]o graduations v]tical & ! prism indicator on upp] z]o4 ,bo? prisms %\ld !n be turn$ simultane\sly ab\t f\r degrees t[>d ! nasal side ( ! pati5t1 ?us t5d+ to jo9tly =ce correspond+ muscles ( bo? eyes4 ,,home ,,treatm5t ,,= ,,muscul> ,,ex]cise--,,squ>e ,,prism ,,set ,,us$ ,,9 ,,conjunction ,,) ,,! ,,ski-,,optomet] ,:]e a pati5t is unable to call ea* day = ?is muscul> treatm5t or ex]cise1 ! "w w be greatly facilitat$ by employ+ a specially design$ set ( squ>e prisms rang+ 9 /r5g? f to #bj degrees = home treatm5t4 ,z 9 ! case previ\sly cit$1 x is necess>y to c>efully in/ruct ! pati5t t ! int]ni muscles mu/ be develop$1 h5ce prism base out ) apex 9 mu/ be employ$4 ,att5tion %\ld !n be direct$ to a c&le light1 s]v+ z a muscle te/+ spot ( light & /ation$ 9 a semi-d>k room at an approximate di/ance ( tw5ty feet4 ,hav+ det]m9$ ?r\gh ! ,ski-optomet] ! /r5g? ( ! prism requir$ aft] ea* (fice treatm5t1 its equival5t %\ld !n be plac$ 9 a special squ>e prism trial-frame :i* p]mits rotation ( ! prism1 al?\gh ! pati5t is frequ5tly taught to twirl ! l5s be=e ! eye4 ,?is ex]cise may be cont9u$ = ab\t five m9utes ea* day4 ,! pati5t %\ld also be in/ruct$ to call at ! end ( ea* week1 :5 ! "w may be *eck$ by means ( ! ,ski-optomet]'s rot>y prisms1 mak+ ! duction te/ z previ\sly expla9$ & outl9$ 9 ,fig4 #bd4 ,x is !n possible to det]m9e :e!r or n satisfactory results are be+ obta9$4 ,o!rwise ! ex]cise %\ld be ab&on$4 ,%\ld ! second me?od employ$ 9 ! "w ( muscul> imbalance n prove effective1 ! ?ird me?od requir+ ! use ( prisms w\ld be next 9 r\t9e4 ,,*apt] ,,xi ,,?ird ,,me?od ,,( ,,treatm5t--,,prism ,,l5ses ,,:5 ,,& ,,h[ ,,employ$ ,z /at$ 9 ! prec$+ *apt]1 on asc]ta9+ ! failure ( ! second muscul> treatm5t or me?od1 prisms are employ$ = con/ant we>4 ,:5 prism l5ses are us$1 :e!r ! case is exophoria or esophoria1 or "r or left hyp]phoria1 x is always safe to prescribe "o-qu>t] degree prism = ea* degree ( prism imbalance = ea* eye4 ,= example1 9 a case ( #f degrees ( esophoria1 a prism ( #a degree base out %\ld be prescrib$ = ea* eye2 or 9 #f degrees ( exophoria1 employ ! same am\nt ( prism1 b base 94 ,9 "r hyp]phoria1 place ! prism base d[n be=e ! "r eye & up be=e ! left1 & vice v]sa = left hyp]phoria4 ,x is n always advisable1 h[ev]1 to all[ ! pati5t to we> ! same degree ( prism = any l5g? ( "t4 ,_m au?orities sugge/ a con/ant *ange ) ! idea t a prism is no?+ m ?an a crut*4 ,%\ld ! same degree be con/antly worn1 ev5 ?\gh x af=d$ tempor>y relief1 ! eye w\ld become accu/om$ to x & ! purpose ( ! prism entirely lo/4 ,prisms %\ld be prescrib$ ) extreme c>e1 _! use be+ id5tical ) t ( dumb-bells1 :]e weight is fir/ increas$ to maximum & subsequ5tly r$uc$1 viz43 ,,prism ,,r$uction ,,me?od ,:]e prisms are prescrib$1 x is consid]$ good practice to make a b9ocul> muscle te/ & ! duction te/ 7,fig4 #bd7 at ! end ( ea* ?ree mon?s' p]iod1 employ+ ! phoromet]1 ,maddox rod1 & rot>y prisms1 z already expla9$4 ,if ! condition %[s any decrease1 ! prism degree %\ld be proportionately decreas$4 ,= example1 9 ! case orig9ally %[+ #f degrees ( exophoria1 "o-qu>t] degree prism = ea* degree ( imbalance 0 prescrib$1 or #a degree = ea* eye4 ,if ! same case subsequ5tly indicat$ #d degrees1 only "o degree = ea* eye %\ld be prescrib$--& s on1 a gradual r$uction ( prism value be+ con/antly s\ght4 ,except 9 r>e cases1 prisms %\ld n be prescrib$ ) ! base or apex at oblique angles1 z ! eye is r>ely at re/ ) su* a correction4 ,an imbalance may be caus$ by a false condition 9 "o rectus & a true imbalance 9 ! o!r1 giv+ "o ! impression t cyclophoria exi/s1 z expla9$ 9 a foll[+ *apt]4 ,hav+ n[ employ$ ! ?ree me?ods1 ! refractioni/ c readily und]/& t a m>k$ p]c5tage ( muscul> imbalance cases may be directly b5efit$ ?r\gh ! aid ( ! ,ski-optomet]4 ,if ^! ?ree me?ods ( proc$ure fail1 !re is no?+ left b ! f\r? & la/ me?od--t ( op]ative proc$ure4 ,,*apt] ,,xii ,a ,,cond5sation ,,( ,,previ\s ,,*apt]s ,,on ,,! ,,proc$ure ,,= ,,muscle ,,te/+ ,,) ,,! ,,ski-,,optomet] ,! pres5t *apt]1 int5d$ = ^? desir+ a synopsis or cond5s$ summ>y ( muscul> imbalance "w1 %\ld prove ( ! utmo/ assi/ance to ! busy refractioni/4 ,muscul> imbalance "w c be successfully conduct$ if ! foll[+ r\t9e is /udi$ & memoriz$1 ) ! ,ski-optomet] con/antly be=e ! read]4 ,! *apt]s conta9+ ! correspond+ figures & diagrams or illu/rations w !n be readily compreh5d$4 ,x is also important to c>efully note ! captions "u ea* diagram4 #a4 ,)\t any te/+ l5ses be=e pati5t's eyes1 direct att5tion to a #bj-;foot di/ant muscle te/+ spot ( light 7,fig4 #i74 #b4 ,place phoromet] h&le v]tically 7,fig4 #af74 ,place r$ ,maddox rod v]tically 7,fig4 #ae74 ,pati5t %\ld see a :ite spot ( light1 & a r$ horizontal /reak 7,fig4 #ag74 ,simply turn phoromet] h&le until horizontal /reak bisects :ite spot ( light4 ,po9t] !n indicates am\nt ( deviation on r$ scale4 ,ignore cases less ?an #a hyp]phoria1 :e!r "r or left designat$ by 7,r4 ,h4--,l4 ,h474 #c4 ,place phoromet] h&le horizontally 7,fig4 #ai74 ,place r$ ,maddox rod horizontally 7,fig4 #ah74 ,pati5t %\ld see a :ite spot ( light & a v]tical r$ /reak 7,fig4 #bj74 ,simply turn phoromet] h&le until r$ /reak bisects spot ( light4 ,po9t] indicates am\nt ( deviation on :ite scale1 :e!r esophoria or exophoria designat$ by 7,es--,ex74 #d4 ,ignore all exophoria cases1 less ?an #c4 ,ignore all esophoria cases1 less ?an #e--;except 9 *ildr51 ignore less ?an #c ( esophoria4 #e4 ,always make ! above or b9ocul> muscle te/--) phoromet] & r$ ,maddox be=e optical correction or 7te/ = sph]es & cyl9d]s7 & aga9 aft] optical correction :]e case %[s m ?an #a-c-e rule1 to det]m9e :e!r muscles are aggravat$ or b5efit$4 #f4 ,9 cases %[+ m ?an ! #a-c-e rule1 %[n 9 above ,no4 #d1 make monocul> duction te/ fir/ ) rot>y prism be=e pati5t's "r eye1--!n ) rot>y prism be=e left eye to f9d faulty muscle & det]m9e :i* eye is affect$4 #g4 ,to te/ adduction1 prism base out is requir$4 ,rot>y prism's r$ l9e or indicator %\ld be rotat$ f z]o outw>dly4 ,to te/ abduction1 base 9 is requir$4 ,indicator %\ld be rotat$ inw>dly f z]o 7,fig4 #bb74 ,p[] ( adduction z comp>$ ) abduction1 is normally #c to #a--usually rat$ #bd to #h4 #h4 ,to te/ sup]duction1 base d[n is requir$4 ,rot>y prism's l9e or indicator %\ld be rotat$ d[nw>d f z]o4 ,to te/ subduction1 base up is requir$4 ,indicator %\ld be rotat$ upw>d f z]o4 ,p[] ( sup]duction z comp>$ ) subduction1 is normally equal--usually rat$ #b = ea* 7,fig4 #bc74 #i4 ,direct pati5t's att5tion to l>ge/ lett] on di/ant *>t1 usually lett] 8,e10 rotat+ r$ l9e indicator ( rot>y prism outl9$ 9 above ,no4 #g & ,no4 #h1 until diplopia is fir/ procur$4 #aj4 ,! use ( a duction *>t on a record c>d1 quickly designates pull = ea* ( f\r muscles 7,fig4 #bd71 illu/rat+ an assum$ case (-- #a/--#f;,d ( ,exophoria4 #bnd--#ah adduction 7:i* mu/ be develop$ to #bd74 #crd--,pati5t has a left weak int]nus4 #aa4 ,employ ,fir/ ,me?od--,optical ,correction--to effect treatm5t4 #ab4 ,assum+ a case ( a *ild ) #f ( esophoria--#h ( "r abduction & #b left abduction indicat+ a left weak ext]nus1 prescribe a qu>t] diopt] increas$ plus sph]ical p[] = ea* degree ( imbalance1 ?us add+ #a4ej;,d sph]ical to optical correction4 ,?is is ! fir/ me?od ( treatm5t4 ,?is requires a ?or\gh read+ ( ,*apt] ,,ix on ,treatm5t = ,correct+ ,esophoria 9 ,*ildr5 & a c>eful /udy ( ! =mula4 ,= synopsis see ,page #gd4 ,,f\r ,,me?ods ,,( ,,treat+ ,,an ,,imbalance ,,case ,,:5 ,,! ,,prec$+ ,,"o ,,fails #a/--,optical correction2 #bnd--,muscul> ex]cise or treatm5t2 #ge ,,are ,,curable ,,) ,,fir/ ,,& ,,second ,,me?ods4 #crd--,prisms2 #e ,,are ,,curable ,,) ,,?ird ,,me?od4 #d?--,op]ation2 #bj ,,are ,,curable ,,) ,,f\r? ,,me?od4 #ac4 ,:5 fir/ me?od ( treatm5t fails1 ,,employ ,,second ,,me?od--,muscul> ,ex]cise--to effect treatm5t4 #a/--,f9d degree ( prism pati5t w accept to produce s+le b9ocul> vision ) optical correction on1 plac+ bo? rot>y prisms 9 position1 h&les horizontal1 r$ l9e on #cj ( temporal scale ( ea*1 giv+ total value to #fj 7,fig4 #bf;a & b74 #bnd--,also place r$ ,maddox rod be=e pati5t's eye 7rods horizontal7 7,fig4 #ah71 call+ pati5t's att5tion to usual muscle te/+ spot ( light4 #crd--,r$uce prism be=e good eye until r$ /reak appe>s1 not+ degree 7:i* we assume %[s #db ! comb9$ total value ( bo? prisms7 sl[ly cont9ue to decrease prism until /reak bisects spot4 ,assume ?is %[s total ( #ch4 ,ei!r side ( #ch 9 excess ( #d 7#ch to #db7 produces diplopia4 ,prisms mu/ only be rotat$ f #ch to #db back to #ch ov] to #cd--;back to #ch ov] to #db--;back aga9 to #ch & s on--ex]cise to be cont9u$ daily t5 times = five m9utes 7,fig4 #bh74 #d?--,at end ( ea* week1 duction te/ %\ld aga9 be made4 ,duction *>t %\ld %[ a t5d5cy to r$uce exophoria by a gradual build+ up ( adduction1 approximately "o week is usually suffici5t to tea* pati5t to hold /reak )9 ! spot 7betwe5 #ch & #db74 ,ex]cise to be cont9u$ until bo? prisms are work$ d[n to z]o4 ,ex]cise t5ds to tea* pati5t h[ to e/abli% same image on ea* fovea or ret9a at same "t4 #e?--,if pati5t is unable to call daily = treatm5t1 employ home treatm5t4 7,read 8,home ,treatm5t = ,muscul> ,ex]cis+10 ,page #hb74 ,employ ,,?ird ,,me?od--,use ( ,prisms = ,con/ant ,we> to effect treatm5t4 ,,prisms #a/4 ,:]e a case _c be r$uc$ ?r\gh use ( fir/ two me?ods1 z = example 9 a case ( #f ( exophoria1 prescribe ( am\nt ( imbalance 7 #f #a7 = ea* eye--base 9--or esophoria base out1 hyp]phoria base up on eye affect$4 #bnd4 ,advise pati5t to call e ?ree mon?s & make duction te/ 7,fig4 #bd74 ,if no improvem5t 9 condition1 aft] we>+ prisms six mon?s1 op]ative means is sugge/$4 ,assume a case is b5efit$1 r$uce prism p[] accord+ to rule2 ,d prism = ea* degree ( imbalance4 ,,cyclophoria ,?is "w be+ ( a te*nical nature1 x is deem$ be/ = ! read] to /udy ,*apt] ,,xiii & ,,xiv4 ,,*apt] ,,xiii ,,cyclophoria ,,made ,,) ,,maddox ,,rods ,,& ,,rot>y ,,prisms ,cyclophoria1 a condition affect+ ! oblique muscles ( ! eye1 is caus$ by its rotation4 ,x is detect$ 9 ! foll[+ mann] by ! comb9$ use ( ! r$ & :ite ,maddox rods & ! rot>y prism4 ,illu/ration3 ,fig4 #bi--,position ( rot>y prism = produc+ diplopia 9 te/+ cyclophoria ) prism plac$ at #h base up4 ,d>k5 ! room & direct ! pati5t's att5tion to ! usual muscle-te/+ spot ( light1 locat$ approximately tw5ty feet away & on a direct plane ) ! pati5t's eye4 ,! optical correction1 if "o is requir$1 %\ld always be left 9 place--j z 9 mak+ o!r previ\sly describ$ muscle te/s4 ,! rot>y prism %\ld !n be br\ght be=e ! pati5t's "r eye ) ! h&le-po9t+ upw>d & ) z]o graduations horizontal4 ,! indicator or r$ l9e %\ld !n be rotat$ upw>d f z]o to eight ^u ! prism scale1 creat+ ! equival5t ( a prism ( #h diopt]s ) base up 7,fig4 #bi74 ,?is normally caus$ diplopia1 al?\gh 9 "s cases x may be necess>y to place ! prism at #aj or #ab degrees be=e diplopia is produc$4 ,illu/ration3 ,fig4 #cj--7;,a4 & ,b47--,fir/ position ( bo? ,maddox rods us$ 9 conjunction ) ,fig4 #bi = det]m9+ cyclophoria4 ,! r$ ,maddox rod %\ld !n be br\ght into op]ative position be=e ! pati5t's left eye 7,fig4 #cj;a7 & ! :ite ,maddox rod be=e ! pati5t's "r eye1 7,fig4 #cj;b7 sett+ ea* "o s t ! rods lie 9 a v]tical position ) _! :ite l9e on ! l>ge r$ z]o 7#j74 ,! pati5t %\ld n[ see two sep>ate & di/9ct /reaks ( light1 "o appe>+ bel[ ! o!r4 ,illu/ration3 ,,det]m9+ ,,cyclophoria ,,"r ,,eye ,,left ,,eye ,fig4 #ca ,fig4 #cd ,,no ,,cyclophoria ,,no ,,cyclophoria ,illu/ration3 ,fig4 #cb ,fig4 #ce ,,cyclophoria ,,cyclophoria ,illu/ration3 ,fig4 #cc ,fig4 #cf - ,,cyclophoria - ,,cyclophoria ,figs4 #ca-cf--;,diagram %[+ h[ /reaks appe> to pati5t1 z produc$ by ! ,maddox rods 9 te/+ = cyclophoria4 ,%\ld !re be no cyclophoria ( ! "r eye1 ! /reaks w appe> 9 a horizontal plane p>allel to ea* o!r 7,fig4 #ca74 ,%\ld ! r$ /reak appe> horizontally to ! left eye1 & ! :ite /reak se5 by ! "r eye appe> at an angle !re)1 cyclophoria ( ! "r eye w\ld be indicat$ 7,fig4 #cb74 ,9 brief1 %\ld ! :ite /reak dip t[>ds ! pati5t's left side1 ! case w\ld be "o ( "r plus cyclophoria 7,fig4 #cb72 :]eas "r m9us cyclophoria w\ld be indicat$ %\ld ! :ite /reak dip to ! pati5t's "r side 7,fig4 #cc74 ,next1 sett+ ! rot>y prism ( #h degrees1 plac$ base up be=e ! pati5t's left eye1 ! r$ /reak %\ld appe> bel[ ! :ite "o4 ,%\ld ! two /reaks appe> horizontally1 p>allel ) ea* o!r1 !re w\ld be no cyclophoria ( ! left eye 7,fig4 #cd74 ,if1 h[ev]1 ! upp] or :ite /reak %\ld appe> horizontal1 & ! l[] or r$ /reak at an angle !re) dipp+ t[>d ! pati5t's "r side1 ! left eye w\ld be cyclophoric & ! case w\ld be "o ( left plus cyclophoria1 z ! *>t indicates 7,fig4 #ce74 ,%\ld ! r$ /reak dip 9 t[>d ! pati5t's left side1 left m9us cyclophoria w\ld be designat$ 7,fig4 #cf74 ,! pati5t w\ld in/9ctively describe1 ) po9t$ f+] & h& motion1 ! position ( ! 8dipp+0 l9e j z "o w\ld describe a spiral /aircase4 ,%\ld ?is te/ det]m9e t no cyclophoria exi/s 9 ei!r eye1 !re w\ld be no necessity = fur!r te/s4 ,"s au?orities claim t bo? ,maddox rods %\ld be ( ! same color1 s z to m readily assi/ ! pati5t to fuse ! two objects4 ,if ! read] s desires1 he c readily place a r$ l5s f ! trial-case 9 ! =w>d cell ( ! in/rum5t4 ,! *>act]s plus & m9us 9 cyclophoria m]ely ref] to plus z signify+ a t5d5cy t[>d ! temporal side2 m9us indicat+ a t5d5cy t[>d ! nasal side4 ,?is has no be>+ on 8convex0 & 8concave10 :i* are frequ5tly designat$ z 8plus0 & 8m9us40 ,! te/ = cyclophoria is p>ticul>ly ess5tial1 prov+ ( utmo/ importance :]e ! pati5t requires an a/igmatic correction ) ! cyl9d] axis 9 oblique m]idian4 ,! case %\ld !n be inve/igat$ 9 e in/ance by mak+ a ?or\gh & sep>ate te/ ( ea* eye = cyclophoria4 ,9 a case :]e cyclophoria is det]m9$1 ! tr\ble may be caus$ by ! function+ ( o!r muscles1 ?r\gh ! dra9 ( n]ve =ce1 ?us di/urb+ ! h>mony ( e muscle action4 ,cyclophoria is frequ5tly caus$ by an imbalance ( two recti1 giv+ an oblique pull4 ,9 mo/ cases1 x is m]ely necess>y to release ! torsion1 z describ$ 9 ! foll[+ *apt]4 ,,*apt] ,,xiv ,,cycloduction ,,te/ ,,made ,,) ,,! ,,comb9$ ,,use ,,( ,,! ,,two ,,maddox ,,rods ,hav+ det]m9$ t cyclophoria exi/s1 z previ\sly outl9$1 ! next /ep w\ld be to make a cycloduction te/1 or a te/ ( ! oblique muscles individually4 ,maddox rods1 bo? r$ & :ite1 %\ld be plac$ 9 position ) ! rods horizontal--! plus & m9us sign at #ij degrees on ! scale 7,fig4 #cg74 ,! pati5t's att5tion %\ld be direct$ to ! usual muscle-te/+ spot ( light1 :5 a v]tical b& ( light w appe> to ! pati5t1 z %[n 9 ,fig4 #ch4 ,illu/ration3 ,fig4 #cg--7;,a4 & ,b47--,prim>y position ( comb9$ use ( bo? ,maddox rods = det]m9+ cycloduction te/4 ,illu/ration3 ,,fig4 #ch ,,normal ,illu/ration3 ,,fig4 #ci ,,"r ,,cycloduction ,,left -,,cycloduction ,illu/ration3 ,,fig4 #dj ,,"r -,,cycloduction ,,left ,,cycloduction ,figs4 #ch-dj--;,diagram %[+ position ( /reaks produc$ by ,maddox rods z !y appe> to pati5ts 9 mak+ cycloduction te/s4 ,to measure ! duction range ( ! inf]ior oblique ( ! "r eye1 x is m]ely necess>y to sl[ly rotate ! ,maddox rod be=e ! "r eye upw>d at its nasal end to ! po9t :]e ! b& ( light breaks s z to resemble a lett] 8,x04 ,?is gives 9 degrees ! am\nt ( "r plus cycloduction1 z indicat$ on ! temporal scale1 :5 x w appe> to ! pati5t1 z %[n 9 ,fig4 #ci4 ,! ,maddox rod %\ld !n be re/or$ to its orig9al position1 ) ! plus & m9us on ! #ij degree l9e ( ! scale 7,fig4 #cg71 & rotat$ upw>d at ! temporal end until x aga9 takes ! =m ( ! lett] 8,x04 7,fig4 #dj47 ,! position ( ! indicator w n[ d5ote ! am\nt ( "r m9us cycloduction1 or duction range ( ! "r sup]ior oblique muscles4 ,hav+ det]m9$ ! duction range ( ! oblique muscles ( ! pati5t's "r eye1 bo? ,maddox rods %\ld be plac$ 9 orig9al position ) rods horizontal & plus & m9us sign on #ij ( scale1 z %[n 9 ,fig4 #cg4 ,! ,maddox rod be=e ! left eye is !n employ$ exactly 9 ! same mann] z be=e :5 ! te/ = ! "r eye 0 made4 ,a plus cycloduction ( ! left eye w\ld be indicat$1 z %[n 9 ,fig4 #dj1 :ile a m9us cycloduction ( ! left eye w\ld appe> to ! pati5t1 z %[n 9 ,fig4 #ci4 ,by record+ a comp>ison ( ea* eye1 z expla9$1 x w be f\nd t ! range ( duction usually av]ages five to tw5ty degrees on ei!r side ( ! #ij degree l9e1 z indicat$ on ! scale surr\nd+ ! ,maddox rods4 ,x w be recall$ t cyclophoria 0 only to be look$ = 9 oblique a/igmatic cases4 ,x is frequ5tly possible to correct ! pati5t's tr\ble1 by *ang+ ! axis ( ! cyl9d]1 be=e "o or bo? eyes1 a m9us cycloduction signify+ a *ange ( axis t[>ds #ahj :ile a plus t[>d #ij1 accord+ to ! am\nt lack+ 9 full duction p[]4 ,x is also well to ex]cise ! oblique muscles ?r\gh a rotation ( ! ,maddox rod be=e ! affect$ eye1 :e!r x be "o or bo? t is lack+ 9 full duction p[]1 until ! requir$ am\nt is rea*$ to equal its fell[ memb]4 ,= a m exhau/ive treatise ! au?or sugge/s a read+ ( ,dr4 ,savage's "w on ! subject4 ,,treatm5t ,,= ,,cyclophoria ,z previ\sly /at$1 x (t5 proves ( great b5efit to employ a muscul> ex]cise :]e a pati5t has an exi/+ cyclophoria ( ei!r "o or bo? eyes1 results d]ivable ?r\gh ! ex]cise ( ! recti muscles hav+ be5 previ\sly detail$4 ,to ex]cise ! oblique muscles ( ! "r eye1 bo? ,maddox rods %\ld be plac$ 9 ! orig9al position employ$ = mak+ cycloduction te/1 z previ\sly expla9$ 7,fig4 #cg74 ,?is causes ! pati5t to see b "o b& or v]tical /reak 7,fig4 #ch74 ,! ,maddox rod1 plac$ be=e ! "r eye1 %\ld be sl[ly rotat$ inw>d f n9ety degrees to a po9t on ! scale :]e ! s+le /reak ( light breaks1 :5 x %\ld aga9 be return$ to n9ety degrees4 ,?is causes a contraction & relaxation ( ! muscles 9 ! =m ( an ex]cise & %\ld be repeat$ t5 times--ab\t five m9utes ea* day4 ,by employ+ ! ,maddox rod be=e ! left eye 9 precisely ! same mann]1 its oblique muscles w be ex]cis$4 ,to det]m9e :e!r or n ?is =m ( ex]cise is b5eficial to ! pati5t1 ! weekly cycloduction te/1 z previ\sly describ$1 %\ld be made & comp>$ ) ! orig9al f9d+s4 ,illu/ration3 ,a ,compact ,phoromet] & ,trial-,frame4 ,,ski-,,optomet] ,,model #bce ,= ,te/+ & ,correct+ ,muscul> ,imbalance--,provid+ a ,com=table ,=m ( ,trial-,frame4 ,,*apt] ,,xv ,,movem5ts ,,( ,,! ,,eyeballs ,,& ,,_! ,,anomalies ,aft] a c>eful /udy ( ! =ego+ *apt]s1 ! refractioni/ may desire fur!r k conc]n+ muscul> imbalance--a matt] 9 :i* ! ,ski-optomet] plays an exceptionally important "p4 ,x %\ld be rememb]$ t x is only ! g5]al utility ( ! in/rum5t1 plus "o's k ( refraction & individual diagnosis t enables ! refractioni/ to atta9 maximum effici5cy 9 e exam9ation1 a fact :i* l>gely acc\nts = ! foll[+ *apt]4 ,,monocul> ,,fixation ,:5 we view an object directly1 s t x appe>s to be m di/9ct ?an surr\nd+ objects1 we are said to 8fix0 or 8fixate0 x4 ,z ! fovea is normally ! mo/ s5sitive "p ( ! ret9a1 af=d+ by f> ! mo/ di/9ct vision1 8fixation10 9 ! great majority ( cases1 is s p]=m$ t ! image ( ! object t is 8fixat$0 falls ^u ! fovea ( ! eye t is 8fix+40 ,?is is kn[n z c5tral or muscul> 8fixation40 ,:5 c5tral vision is abs5t1 h[ev]1 ! pati5t is compell$ to see ) a portion ( ! ret9a outside ( ! fovea4 ,! eye mu/ !n be s direct$ z to cause ! image ( ! object to fall on ?is outly+ portion ( ! ret9a4 ,?is is t]m$ 8ecc5tric fixation10 & usually d5otes t vision is exceptionally poor4 ,! ability to 8fix0 is app>5tly acquir$ 9 e>ly infancy by con/ant practice 9 look+ at objects4 ,any m>k$ int]f]5ce ) vision1 p>ticul>ly ) c5tral vision--pres5t at bir? or soon !reaft]--w t5d to prev5t ! acquisition ( ?is ability1 & 9 extreme cases ! eye does n le>n to 8fix0 at all1 b aimlessly w&]s 9 all directions4 ,,b9ocul> ,,fixation ,we habitually use ! eyes toge!r1 fixat+ ) bo? at once2 t is1 we direct ! eyes 9 su* a way t ! image ( ! object to :i* ! att5tion is direct$ falls on ! fovea ( ea* eye4 ,:]e bo? eyes are accurately direct$ to an object at :i* "o or bo? are look+1 ! condition is kn[n z 8b9ocul> fixation10 :i* is commonly und]/ood to mean t bo? eyes are /raight4 ,! ability to produce & ma9ta9 b9ocul> fixation--to keep bo? eyes directly /raight--is acquir$ e>ly 9 life4 ,! impulse to ma9ta9 x gr[s ) ex]cise1 & soon becomes s /rong t aft] ! age ( infancy b9ocul> fixation is pres5t 9 ! great majority ( p]sons1 & 9 mo/ ( !m is pres5t all ! "t4 ,b9ocul> fixation mu/ be di/+ui%$ ?r\gh ?ree conditions--or?ophoria1 het]ophoria & squ9t4 ,,or?ophoria ,?is is ! condition 9 :i* bo? eyes look /raight at ! same object1 :e!r bo? see x or n4 ,!re is n ! slighte/ t5d5cy ( deviation4 ,,het]ophoria ,?is is ! condition 9 :i* bo? eyes keep look+ /raight at ! same object s long z bo? see x2 b z soon z "o eye is exclud$ f vision 7z by a scre57 t eye deviates4 ,?is is !n a t5d5cy ( deviation :i* is /rong en\gh to become manife/ :5 ei!r eye is cov]$1 b :i* is aboli%$ or ov]come by ! compell+ impulse ( b9ocul> fixation z soon z bo? eyes are us$ = see+4 ,a het]ophoria ?us produces a maximum deviation4 ,! deviation is also said to be lat5t1 s9ce x is abs5t "u ord9>y conditions & is br\ght to light only "u special conditions4 ,a common ?\gh improp] t]m = het]ophoria is 8insuffici5cy40 ,,squ9t ,squ9t is ! condition 9 :i* !re is s great a t5d5cy to deviation t ev5 :5 bo? eyes are uncov]$1 "o deviates & only "o 8fixes40 ,x diff]s1 !re=e1 f het]ophoria 9 t ! deviation x produces is obvi\s "u ord9>y conditions4 ,squ9t is also call$ /rabismus1 or het]otropia4 ,9 o!r words1 9 or?ophoria !re is b9ocul> fixation all ! "t & "u all conditions2 9 het]ophoria x is pres5t only :5 ! two eyes are uncov]$1 s t bo? see ! object look$ at2 :ile 9 squ9t x is n pres5t at all4 ,or1 9 /ill pla9] t]ms1 9 or?ophoria bo? eyes are /raight all ! "t2 9 het]ophoria bo? are /raight1 b only s long z bo? are uncov]$2 & 9 squ9t only "o eye is /raight1 no matt] :e!r bo? eyes are uncov]$ or n4 ,9 squ9t1 :ile b9ocul> fixation is altoge!r abs5t1 ! ability to p]=m monocul> fixation is almo/ always pres]v$2 i4e41 ! squ9t+ eye w 8fix0 at once if ! o!r eye is cov]$4 ,x is only :5 !re is m>k$ amblyopia1 p>ticul>ly z ! result ( a c5tral scotoma 7or spot on ! cornea 9 ! l9e ( vision7 t ! squ9t+ eye loses its p[] to fix at all1 & w&]s unc]ta9ly ab\t1 receiv+ impressions n[ on "o1 n[ on ano!r portion ( ! ret9a4 ,! t]m imbalance is (t5 us$ to d5ote ! two conditions oppos$ to or?ophoria2 i4e41 to d5ote collectively het]ophoria & squ9t4 ,,v>ieties ,,( ,,het]ophoria ,,& ,,squ9t #a4 ,classification ,accord+ to ,direction ( ,deviat+ ,eye3 ,het]ophoria & squ9t may be classifi$ accord+ to ! direction assum$ by ! deviat+ eye4 ,?us we h ! foll[+ v>ieties ( het]ophoria3 ,,het]ophoria ,,lat]al ,,deviations ,ei!r eye deviates ,91 or t[>d ! nose ,esophoria ,out1 or t[>d ! temple ,exophoria ,,v]tical ,,deviations ,! "r eye goes up & ! left d[n ,"r ,hyp]phoria ,! left eye goes up & ! "r d[n ,left ,hyp]phoria ,9 r>e cases ( v]tical het]ophoria1 ea* eye has ei!r an upw>d t5d5cy 7anophoria7 or a d[nw>d t5d5cy 7cataphoria74 ,^! cases mu/ n be confus$ ) anatropia & catatropia4 ,9 anaphoria & cataphoria1 !re is b9ocul> fixation :5 bo? eyes are uncov]$1 :ile 9 anatropia & catatropia "o ( ! eyes squ9ts4 ,?is %[s ! foll[+ squ9t condition3 ,,squ9t ,,lat]al ,,squ9t ,! deviat+ eye turns 91 or t[>d ! nose3 ,esotropia 7,/rabismus conv]g5s--,conv]g5t ,squ9t7 ,! deviat+ eye turns out or t[>d ! temple3 ,exotropia 7,/rabismus div]g5s--,div]g5t ,squ9t7 ,,v]tical ,,squ9t ,! deviat+ eye turns up3 ,hyp]tropia 7,/rabismus sursumv]g5s7 7,"r or left7 ,! deviat+ eye turns d[n3 ,hypotropia 7,/rabismus deorsumv]g5s7 7,"r or left7 ,9 addition to ^! lat]al & v]tical deviations1 conditions exi/ 9 :i* ! v]tical m]idian ( "o eye1 in/ead ( ma9ta9+ its p>allelism ) ! v]tical m]idian ( ! o!r1 ei!r =ms 7or t5ds to =m7 an angle ) x 7cyclotropia71 b is kept 9 position ?r\gh muscul> ef=t 7cyclophoria47 ,cyclotropia is usually due to p>alysis ( "o ( ! ocul> muscles1 caus+ ! v]tical m]idian ( ! affect$ eye to be tilt$ out or t[>d ! temple 7extorsion7 or 9 t[>d ! nose 7intorsion74 ,a tilt+ ( ! v]tical m]idian t[>d ! "r is also call$ dextrotorsion 7or positive decl9ation72 & to ! left1 levotorsion or negative decl9ation4 #b4 ,con/ant1 ,int]mitt5t & ,p]iodic ,deviations3 ,a deviation1 :e!r squ9t or het]ophoria1 may be pres5t at all times 7con/ant71 or occasionally pres5t & occasionally abs5t 7int]mitt5t74 ,9 ?is case we may h het]ophoria alt]nat+ ) or?ophoria1 or het]ophoria alt]nat+ ) squ9t2 or squ9t alt]nat+ ) or?ophoria4 ,we also f9d v>iations su* z a squ9t = ne> & a het]ophoria or or?ophoria = di/ance2 or a het]ophoria = ne> & or?ophoria = di/ance2 or a con/ant squ9t = ne> & an int]mitt5t squ9t = di/ance1 etc4 ,aga91 a deviation may be p]iodic1 9 t its am\nt = di/ance may greatly exce$ t = ne>1 or vice v]sa4 ,oppos$ to a p]iodic deviation is "o :i* is pres5t1 & 9 ab\t equal am\nt1 bo? = di/ance & ne>4 ,su* a deviation1 :e!r squ9t or het]ophoria1 is call$ 8cont9u\s40 #c4 ,alt]nat+ & ,uniocul> ,squ9t3 ,an alt]nat+ squ9t is "o 9 :i* :5 bo? eyes are uncov]$1 s t bo? h a *ance to 8fix02 sometimes ! "r eye w deviate1 sometimes ! left4 ,9 uniocul> 7less prop]ly monocul>7 squ9t1 "u ! same conditions1 "o eye1 ei!r ! "r or ! left1 always 8fixes0 & ! o!r always deviates4 ,a uniocul> squ9t is d5ot$ z "r or left1 accord+ to :e!r x is ! "r or left eye :i* deviates4 ,illu/ration3 ,a ,,typical ,,refraction ,,room--,,! ,,woolf ,,sanit>y ,,all-,,metal ,,equipm5t ,in/allation compris+3 ,oph?almic ,*air1 complete ) ,ski-optomet]1 ,te/ ,lett] ,cab9et1 ,asceptic ,trial-,case ,cab9et1 ,muscle ,te/+ & ,skioscopic ,lamp1 ,oph?almomet]1 ,p]imet]1 ,adju/able ,tables1 ,adju/able ,/ool4 #d4 ,comitant & ,non-,comitant ,deviations3 ,9 "s v>ieties ( het]ophoria & squ9t1 ! am\nt ( deviation is ! same 9 all directions ( ! gaze1 s t ! angle betwe5 ! visual l9e ( "o eye & t ( ! o!r rema9s ! same1 no matt] :i* way ! eyes are turn$4 ,su* deviations are call$ comitant or non-comitant1 because "o eye accompanies & keeps pace ) ! o!r 9 all its movem5ts4 ,9 o!r cases1 ! deviation *anges z ! eyes are mov$ 9 diff]5t directions1 s t ! angle betwe5 ! two visual l9es con/antly v>ies4 ,su* deviations are t]m$ concomitant4 ,usually 9 a non-comitant squ9t ! angle ( deviation increases 9 a regul> way z ! eyes are mov$ 9 "o direction & decreases z !y move 9 ! direction opposite4 ,9 cases ( long /&+1 h[ev]1 ! squ9t+ eye1 p>ticul>ly :5 v amblyopic1 w&]s 9 an unc]ta9 way & app>5tly q )\t ref]5ce to ! movem5ts ( ! o!r eye4 ,,*apt] ,,xvi ,,law ,,( ,,projection ,! movem5ts ( ! eye are design$ prim>ily to effect fixation--t is1 to br+ ^u ! macula ! image ( ! object t we wi% to look at4 ,:5 ?is has be5 accompli%$1 we "k z a result ( long exp]i5ce1 ! direction ( ! object look$ at & also direction ( o!r neighbor+ objects4 ,?is k is d\btless af=d$ u1 9 "p1 by our muscle s5se4 ,?us we "k t an object1 ,a1 is /raight 9 front ( u because we c see x %>ply )\t mov+ ei!r ! head or ! eyes f ! position ( re/ or equilibrium2 & we "k t an object1 ,b1 is on ! "r ( u because to see x %>ply we h to move ei!r ! head or ! eyes to ! "r1 ?us alt]+ ! muscul> condition f "o ( re/ to "o ( t5sion4 ,b )\t mov+ ei!r head or eye1 we also "k1 :ile /ill look+ at ,a1 t ,b is to ! "r1 = ! image ( ,b is !n =m$ on a portion ( ! ret9a situat$ to ! left ( ! macula4 ,f long exp]i5ce we also "k t an image s situat$ means an object plac$ on our "r4 ,moreov]1 ! f>!r to ! left ( ! macula ! image ,b is1 ! f>!r to ! "r d we judge ,b itself to be4 ,simil>ly1 if ,b is s plac$ t its image falls bel[ ! macula1 we !n "k ,b itself is really above ,a1 :i* =ms its image on ! macula2 & if ! image ( ,b is above ! macula1 we "k t ,b itself is bel[ ,a4 ,! table on page #aaf is sugge/$ z a guide 9 cases ( muscul> imbalance3 ,,suppression ,,( ,,image ,all deviations %\ld be & probably are prim>ily associat$ ) diplopia4 ,yet 9 ! great majority ( cases ( e/abli%$ squ9t1 especially conv]g5t squ9t1 !re is no d\ble vision4 ,?is is due to ! m5tal suppression ( ! image by ! squ9t+ eye4 ,9 su* cases all attempts to evoke diplopia by our te/s may be futile1 ! pati5t n appreciat+ ! pres5ce ( d\ble images ev5 :5 !y are widely sep>at$ by prisms4 ,moreov]1 ?is suppression usually p]si/s aft] ! squ9t is cur$1 s t ev5 ?\gh !re are two ret9al images ( ! same object1 ! m9d p]ceives b "o & ignores ! o!r1 j z ?\gh x 7 n pres5t4 ,9 ?is case !re is no true /]eoscopic1 or solid1 vision4 ,,monocul> ,,diplopia ,b9ocul> diplopia1 due to deviation ( ! eyes or to prisms1 mu/ be di/+ui%$ f monocul> diplopia1 or ! condition 9 :i* ! pati5t sees d\ble ) "o eye alone4 ,?is occurs z ! result ( a/igmatism1 plus sph]ical ab]ration & o!r conditions f\nd occasionally 9 squ9t4 ,x c readily be diff]5tiat$ by ! fact t b9ocul> diplopia disappe>s :5 ! pati5t %uts ei!r eye2 :ile monocul> diplopia1 ( c\rse1 does n4 ,,table ,,( ,,diplopia ,image ( "r eye ,,caus$ ,,by z comp>$---------------------------------- -- ,"n ( ) t 7#b7 ,artificially diplopia ( ! 7#a7 ,by a natural by a prism left is deviation ( plac$1 base ---------------------------------------- ------------------------- ,homonym\s ,on ! ,ei!r eye inw>d ,9 be=e ei!r "r 7esophoria1 eye4 ,lat- esotropia47 eral ,het]onym\s ,on ! ,ei!r eye outw>d ,out be=e ei!r 7or cross$7 left 7exophoria1 eye4 exotropia47 ---------------------------------------- ------------------------- ,"r ,bel[ ,"r eye up ,up be=e "r or left eye d[n eye1 d[n be=e ,v]t- 7"r hyp]phoria1 left eye4 ical "r hyp]tropia1 left hypotropia47 ,left ,above ,"r eye d[n ,d[n be=e "r or left up eye1 up be=e 7left hyp]phoria1 left left hyp]tropia1 "r hypotropia47 ,image ( "r eye ,,correct$ ,,by z comp>$---------------------------------- -- ,"n ( ) t diplopia ( ! 7#a7 ,turn+ 7#b7 ,prism plac$ left is ) base ---------------------------------------- ------------------------- ,homonym\s ,on ! ,bo? eyes outw>d ,out be=e ei!r "r 7div]g5ce47 eye4 ,lat- eral,het]onym\s ,on ! ,bo? eyes inw>d ,9 be=e ei!r 7or cross$7 left 7conv]g5ce47 eye4 ---------------------------------------- ------------------------- ,"r ,bel[ ,"r eye d[n ,d[n be=e "r ,v]t- & left eye up eye or up be=e ical 7left left eye4 suprav]g5ce47 ,left ,above ,"r eye up & ,up be=e "r left eye d[n eye or d[n 7"r be=e left4 suprav]g5ce47 ,,movem5t ,,( ,,ea* ,,eye ,,s+ly ,! movem5ts ( ea* eye individually are effect$ z foll[s3 ,! ext]nal rectus moves ! eye directly outw>d2 ! int]nal rectus1 directly inw>d4 ,! prim>y action ( ! sup]ior rectus is to raise ! eye4 ,because ( ! way 9 :i* ! muscles run1 obliquely f )9 outw>d1 its lift+ action increases :5 ! eye is abduct$ & dim9i%es to little or no?+ :5 ! eye is adduct$4 ,! inf]ior rectus c>ries ! eye d[n4 ,ow+ to ! oblique direction ( ! muscle1 its depress+ action increases z ! eye is abduct$ & decreases to z]o z ! eye is adduct$4 ,! inf]ior oblique is ins]t$ back ( ! equator ( ! eye4 ,h5ce x pulls ! back "p ( ! eye d[n & consequ5tly ?r[s ! front "p up4 ,x is ?us an elevator ( ! eye1 re9=c+ ! action ( ! sup]ior rectus4 ,ow+ to ! way 9 :i* x runs1 f ! front backw>d & outw>d1 its elevat+ action is greate/ :5 ! eye is adduct$1 & dim9i%es to little or no?+ :5 ! eye is abduct$4 ,! sup]ior oblique1 s f> z its action on ! eyeball is conc]n$1 may be reg>d$ z aris+ f ! tro*lea4 ,f ?is po9t x runs backw>d & outw>d & is ins]t$ back ( ! equator ( ! eye4 ,x !re pulls up ! back "p ( ! eye & consequ5tly ?r[s ! front "p d[n4 ,x is ?us a depressor1 re9=c+ ! action ( ! inf]ior rectus4 ,ow+ to ! oblique way 9 :i* x runs1 its depress+ action is greate/ :5 ! eye is adduct$1 & dim9i%es to little or no?+ :5 ! eye is abduct$4 ,,subsidi>y ,,actions ,besides ^! actions1 rightly reg>d$ z ! ma9 action ( ! ocul> muscles1 !re are v>i\s subsidi>y actions1 due to ! oblique way 9 :i* ! sup]ior & inf]ior recti & ! two obliques run4 ,?us1 bo? ! sup]ior & inf]ior recti adduct ! eye1 _! action be+ mo/ pron\nc$ :5 ! eye is already adduct$4 ,! two obliques1 on ! o!r h&1 abduct ! eye & d s mo/ effectively :5 ! eye is already abduct$4 ,! sup]ior rectus & sup]ior oblique rotate ! top ( ! v]tical m]idian ( ! eye inw>d 7intorsion72 :ile ! inf]ior oblique & inf]ior rectus rotate x outw>d 7extorsion74 ,! sup]ior & inf]ior recti act ?us on ! v]tical m]idian ma9ly :5 ! eye is adduct$2 ! oblique1 on ! o!r h&1 :5 ! eye is abduct$4 ,h5ce ! eye is adduct$ by ! int]nal rectus1 assi/$ t[>d ! end ( its c\rse by ! sup]ior & inf]ior recti4 ,x is abduct$ by ! ext]nal rectus1 assi/$ t[>d ! end ( its c\rse by ! two obliques4 ,x is c>ri$ /raight up by ! sup]ior rectus & inf]ior oblique1 up & out by ! sup]ior rectus & ext]nal rectus 7! inf]ior oblique help+ to c>ry x out1 b n up2 & 91 ma9ly by ! inf]ior oblique & int]nal rectus74 ,! sup]ior rectus assi/s 9 c>ry+ x 91 b h>dly up at all4 ,! eye is likewise c>ri$ /raight d[n by ! inf]ior rectus & ! sup]ior oblique2 d[n & out by ! inf]ior & ext]nal recti1 & d[n & 9 by ! sup]ior oblique & int]nal recti4 ,,field ,,( ,,action ,,( ,,muscles ,z w be se51 ea* muscle acts mo/ en]getically 9 "s special direction ( ! gaze1 t]m$ field ( action ( t p>ticul> muscle2 ?us ! ext]nal rectus acts mo/ p[]fully :5 ! eye is direct$ outw>d1 & acts little or n at all :5 ! eye is direct$ inw>d1 except by purely passive traction4 ,likewise ! sup]ior rectus acts ma9ly :5 ! eye is direct$ d[n4 ,fur!rmore1 its action is limit$ to ! upp] & out] field2 = 9 ! upp] & inn] field elevation is p]=m$ *iefly by ! inf]ior oblique4 ,?is is also true ( all ! o!r muscles4 ,,direction ,,( ,,! ,,gaze ,!re are six c>d9al directions ( ! gaze1 ea* correspond+ to ! field ( action ( "o ( ! six ocul> muscles z foll[s3 ,,c>d9al ,,direction3 ,,muscles ,,specially ,,active3 ,/raight out ,ext]nal rectus ,/raight 9 ,int]nal rectus ,up & out ,sup]ior rectus 7z an elevator7 ,up & 9 ,inf]ior oblique 7z an elevator7 ,d[n & out ,inf]ior rectus 7z a depressor7 ,d[n & 9 ,sup]ior oblique 7z a depressor7 ,x is to be not$ t ! action ( ea* muscle does n absolutely /op at ! middle l9e1 b ext5ds some:at beyond x4 ,?us ! action ( ! "r ext]nus ext5ds n only ?r\gh\t ! :ole "r half ( ! field ( vision1 b also "s fifte5 to tw5ty degrees to ! left ( ! m$ian l9e2 & t ( ! sup]ior rectus ext5ds n only above ! horizontal plane b also some:at bel[4 ,,prim>y ,,position--,,field ,,( ,,fixation ,"u normal conditions1 :5 ! head is erect & ! eye is direct$ /raight =w>d--t is1 :5 its l9e ( sight is p]p5dicul> to ! l9e jo9+ ! c5tres ( rotation ( ! two eyes 9 ! horizontal plane--! muscles are all balanc$4 ,?is is call$ 8! position ( equilibrium0 or ! prim>y position4 ,x is ?is position :i* mu/ be assum$ by ! pati5t 9 conduct+ te/s = balance ( ! muscles4 ,f ! prim>y position1 ! eye may make excursions 9 e direction s t ! pati5t c look at a :ole s]ies ( objects 9 succession )\t mov+ ! head4 ,?is portion ( space1 occupi$ by all ! objects t may ?us be se5 directly by mov+ ! eye )\t mov+ ! head1 is call$ 8! field ( fixation40 ,,b9ocul> ,,movem5ts ,:ile ei!r eye alone may move 9 all possible directions1 "o _c move indep5d5tly ( ! o!r eye4 ,"u ord9>y circum/ances1 ^? movem5ts only are possible :i* are regul>ly requir$ to subs]ve b9ocul> vision1 h5ce1 b9ocul> s+le vision1 z well4 ,^! movem5ts are z foll[s3 ,,p>allel ,,movem5ts ,:5 "o eye looks at a di/ant object ! o!r is also direct$ to x1 s t ! l9es ( sight ( ! two eyes are p>allel2 if ! di/ant object is mov$ ab\t1 ! l9es rema9 p>allel1 "o mov+ z fa/ & z f> z ! o!r4 ,^! p>allel movem5ts ( ! two eyes are execut$ ) consid]able fre$om 9 all directions1 ei!r eye be+ able to move readily to ! "r1 left1 up1 d[n1 or obliquely1 provid$ ! o!r eye moves precisely ) x4 ,9 execut+ any p>allel movem5t1 ea* eye is act$ ^u by at lea/ ?ree & sometimes by z _m z five muscles4 ,at times1 b "o ( ^! muscles is requir$ to produce any great movem5t ( ! eye1 ! o!rs simply s]v+ to /eady x 9 its c\rse4 ,?us :5 we look up to ! "r1 al?\gh !re are five muscles really act+ ^u ea* eye1 ! "r eye is mov$ ma9ly by ! ext]nal rectus & ! left eye by ! int]nal rectus4 ,simil>ly1 :5 we look up & to ! "r1 al?\gh o!r muscles take "p1 ! sup]ior rectus is ! *ief muscle t moves ! "r eye up1 & ! ext]nal rectus ! *ief "o t moves x to ! "r2 :ile = ! left eye ! inf]ior oblique & ! int]nal rectus are ! effici5t muscles4 ,a c>eful /udy ( ! action ( ! individual muscles w make x cle> t ^! facts hold good = ea* ( ! c>d9al directions ( ! gaze4 ,fur!rmore1 if we att5tively consid] ! action ( ! twelve muscles mov+ ! two eyes1 we see t !y may be divid$ into ?ree gr\ps1 viz42 f\r lat]al rotators1 f\r elevators & f\r depressors4 ,,lat]al ,,rotators ,"r rotators ,left rotators ,l4 ,int]nal rectus to ,r4 ,int]nal rectus ,r4 ,ext]nal rectus ,l4 ,ext]nal rectus ,,elevators ,"r-h&$ elevators ,left-h&$ elevators 7act+ ma9ly :5 ! 7act+ ma9ly :5 ! eyes are direct$ to ! to eyes are direct$ to ! "r7 left7 ,r4 ,sup]ior rectus ,r4 ,inf]ior oblique ,l4 ,inf]ior oblique ,l4 ,sup]ior rectus ,,depressors ,"r-h&$ depressors ,left-h&$ depressors 7act+ ma9ly :5 ! 7act+ ma9ly :5 ! eyes are direct$ to ! eyes are direct$ to ! "r7 to left7 ,r4 ,inf]ior oblique ,r4 ,sup]ior oblique ,l4 ,sup]ior oblique ,l4 ,inf]ior rectus4 ,ea* gr\p1 x w be se51 comprises two pairs ( muscles2 "o pair act+ solely :5 ! eyes are direct$ to ! "r1 ! o!r :5 !y are direct$ to ! left4 ,x w fur!r be not$ t ( ! two muscles con/itut+ any "o pair1 "o is situat$ 9 ! "r eye1 ! o!r 9 ! left4 ,,eye ,,associates ,! muscles =m+ any "o pair are call$ associates4 ,any two associates act+ toge!r w move _! respective eyes 9 precisely ! same direction & to ! same ext5t4 ,?us ! "r sup]ior rectus moves ! eye up to ! left & rotates its v]tical m]idian to ! left2 & its associate1 ! left inf]ior oblique1 moves its eye up to ! left & rotates its v]tical m]idian to ! left4 ,?is likewise applies to ea* ( ! o!r five gr\ps ( associates4 ,if "o eye fails to keep pace ) ! o!r 9 execut+ p>allel movem5ts1 diplopia ensues4 ,if ! eyes are mov$ 9 all directions & ! po9t not$ :]e ! pati5t j beg9s to see d\ble1 we delimit ! field ( b9ocul> s+le vision4 ,normally1 h[ev]1 ! two eyes ma9ta9 p>allelism to ! v limit ( _! excursion1 s t diplopia occurs only at ! extreme p]iph]y ( ! field ( vision1 if at all4 ,9 fact1 ! field ( b9ocul> s+le vision usually ext5ds n less ?an #dj degrees f ! prim>y position 9 e direction4 ,ea* ( ! v>i\s p>allel movem5ts ( ! eye appe> to be gov]n$ by a di/9ct n]ve me*anism1 !re be+ "o c5tre = movem5ts to ! "r1 "o = movem5ts to ! left1 "o = movem5ts up1 etc4 ,,movem5ts ,,( ,,conv]g5ce ,9 ord] to see an object at a ne>by po9t1 ! eyes h to conv]ge--a movem5t affect$ by a simultane\s & equal contraction ( bo? int]nal recti4 ,?is movem5t may be comb9$ ) a v]tical1 lat]al or oblique p>allel movem5t4 ,?us1 :5 we wi% to look at a ne> object situat$ tw5ty degrees to our "r1 we fir/ turn bo? eyes tw5ty degrees to ! "r1 !n conv]ge bo? equally1 turn+ ! left a little m to ! "r & ! "r a little back t[>d ! left4 ,conv]g5ce is gov]n$ by a di/9ct me*anism ( ! n]ves1 ! s\rce ( :i* has n be5 det]m9$4 ,,movem5ts ,,( ,,div]g5ce ,9 pass+ f a position ( conv]g5ce to a position ( p>allelism1 ! l9es ( sight sep>ate or div]ge4 ,?is movem5t ( div]g5ce is a simultane\s1 equal contraction ( bo? ext]ni2 or1 probably1 ( bo? actions comb9$4 ,! eyes may ev5 div]ge some:at beyond p>allelism1 z 9 ov]com+ prisms1 base 91 :5 look+ at a di/ant object4 ,,v]tical ,,div]g5ce ,! am\nt by :i* ! l9es ( sight c sep>ate 9 a v]tical direction is v limit$--at mo/ b "o or two degrees4 ,,or?ophoria ,! t]m or?ophoria is us$ to d5ote an absolutely normal balance ( ! extr9sic muscles1 j z ! t]m emmetropia d5otes a normal refractive condition4 ,!y are equally r>e4 ,,het]ophoria ,! t]m het]ophoria includes all ^? conditions 9 :i* !re is a t5d5cy to dep>t f normal balance1 b :i* nature is able to comp5sate =2 :ile ! t]m also includes ! conditions 9 :i* nature has be5 unequal to ! task & an actual turn+ or squ9t has occurr$4 ,,subdivisions ,! subdivisions ( ^! t]ms at fir/ read+ appe> complicat$1 b prove simple en\gh on clos] /udy1 indicat+ only ! direction ( ! turn+ or t5d5cy to turn4 ,= in/ance3 ,esophoria signifies inw>d t5d5cy4 ,exophoria signifies outw>d t5d5cy4 ,hyp]phoria signifies upw>d t5d5cy4 ,hypophoria signifies d[nw>d t5d5cy4 ,cyclophoria signifies t5d5cy to torsion4 ,esotropia signifies inw>d turn+4 ,exotropia signifies outw>d turn+4 ,hyp]tropia signifies upw>d turn+4 ,hypotropia signifies d[nw>d turn+4 ,cyclotropia signifies actual torsion4 ,comb9ations are describable 9 simil> t]ms4 ,a t5d5cy ( ! "r eye to turn up & inw>d1 is a 8"r hyp]esophoria02 ! left eye to turn d[n & out1 a 8left hyp]exophoria10 etc4 ,t5d5cies ( bo? eyes toge!r are d5ot$ by ! t]ms :i* foll[3 ,anaphoria signifies an upw>d t5d5cy4 ,kataphoria signifies a d[nw>d t5d5cy4 ,dextrophoria signifies a "r t5d5cy4 ,laevophoria signifies a left t5d5cy4 ,,*apt] ,,xvii ,,symptoms ,,( ,,het]ophoria ,^! dep5d on ! k9d ( error pres5t z well z ! degree & widely v>y4 ,9 g5]al1 !y may be said to fall into ?ree classes--7#a7 defective vision1 7#b7 pa9 ( great] or less degree--7#c7 reflex symptoms4 ,defective ,vision4 ,! fir/ class may be pres5t1 ev5 ?\gh ea* eye has a normal visual acuity2 s9ce1 ev5 :5 comp5sation is v good1 ! bra9 gets ! impression ( two objects1 ne>ly1 ?\gh n q fus$2 & vision may be consid]ably worse ) bo? eyes toge!r ?an ) ei!r eye s+ly4 ,:5 comp5sation is consid]ably impair$1 ! diplopia becomes m & m p]si/5t1 till ! bra9 f9ally makes *oice ( "o image z m satisfactory1 entirely suppress+ ! o!r4 ,visual acuity may n suff] 9 ei!r eye2 b vision be+ no long] b9ocul>1 ev]y?+ is se5 9 ! flat1 ! judgm5ts ( dep? & di/ance be+ regul>ly m or less defective4 ,:ile ?is is a trem5d\s disadvantage 9 _m occupations1 p gradually & n infrequ5tly become accu/om$ to ^! visual defects & are n consci\s ( ! h&icap4 ,pa94 ,x is q diff]5t ) ! second set ( symptoms1 :i* are always accompani$ ) pa94 ,9 fact1 ! "* ( ! subjective symptoms 9 refractive errors & muscul> imbalance is s simil> t x is practically impossible to diff]5tiate 9 _m cases4 ,9 muscul> a/h5opia1 h[ev]1 9 addition to becom+ easily tir$1 ! pati5t (t5 compla9s t lett]s seem to jump or run toge!r or he may cont5d t he sees d\ble = an in/ant2 or aga9 t he c 8feel 8 eyes turn0 involunt>ily 9 _! sockets4 ,^! pa9s or conditions are sometimes pres5t only dur+ actual use ( ! eyes4 ,at o!r times !y p]si/ = h\rs4 ,9 "s cases1 aft] days or weeks ( ov]/imulation1 an explosion 9 migra9e =m occurs at irregul> int]vals4 ,?is condition (t5 la/s a day or two4 ,reflex ,symptoms4 ,9 ! ?ird & la/ case1 !re are o!r reflex symptoms--su* z dizz9ess1 nausea1 fa9t+1 indige/ion1 insomnia & pa9s 9 o!r portions ( ! body--sometimes /imulat+ organic diseases4 ,! possibility ( het]ophoria z a factor 9 *orea1 migra9e1 neura/h5ia & o!r diseases :i* may be prim>ily due to un/able n]ves1 equilibrium is n to be =gott54 ,x is a notable fact t :5 ! fusion comp5sation fails s completely t "o image is entirely suppress$1 or ! diplopia is s great z to be ov]look$1 ! symptoms (t5 cease entirely4 ,,treatm5t ,! treatm5t ( het]ophoria dep5ds on a c>eful /udy ( ea* individual case1 b x _c be too /rongly emphasiz$ t 9 ! great majority ( cases ! subjective symptoms disappe> aft] a full correction ( ! refraction is made4 ,9 _m cases1 if ! visual acuity 9 ea* eye be made normal1 ! fusion impulse alone w be suffici5t to re/ore comp5sation4 ,_m cases ( esophoria result f ov]/imulation ( ! c5t]s = conv]g5ce & accommodation1 made necess>y by hyp]opia & a/igmatism1 entirely disappe>+ :5 glasses aboli% ! ne$ ( accommodation4 ,cases ( exophoria are sometimes due to ! abnormal relaxation ( accommodation & conv]g5ce :i* secures ! be/ di/ant vision 9 myopia4 ,likewise ! correction ( myopia1 by increas+ ! f> po9t1 may dim9i% ! am\nt ( conv]g5ce necess>y = ne> vision4 ,prisms = con/ant use are (t5 prescrib$1 s plac$ z to help ! weak muscles & c\nt]act ! /rong4 ,= in/ance1 9 esophoria we f9d ! prism :i*1 base 91 w produce or?ophoria = di/ance & prescribe a qu>t] ( x1 base 91 be=e ea* eye4 ,:ile ?is is v successful 9 "s cases1 ! t5d5cy 9 o!rs is = ! ext]nus to increase slightly f con/ant ex]cise 9 ov]com+ ! prism1 :ile ! int]nus decreases 9 proportion to ! am\nt ( "w ( :i* x is reliev$4 ,prisms = p]man5t use are v b5eficial 9 v]tical deviations1 s9ce :5 ! images are br\ght on ! same level !y require mu* less ef=t to secure fusion2 & :5 prescrib$ base up or d[n1 ! effect secur$ is commonly an un*ang+ "o4 ,we sometimes take advantage ( ?is t5d5cy :5 we prescribe = con/ant use weak prisms ) ! apex ov] ! weak muscle1 :i* gradually becomes /rong f ! ex]cise ( ov]com+ x4 ,?is plan is effective only 9 pati5ts :o h a /rong fusion impulse1 & ! prism select$ mu/ be weak en\gh to be easily ov]come4 ,we c accompli% ! same effect by dec5t]+ ! pati5t's refraction l5ses4 ,= in/ance1 a convex l5s s plac$ t ! visual l9e passes ! rev]se w be ! case if ! l5s is concave4 ,! am\nt ( prismatic action dep5ds on ! /r5g? ( ! l5s & ! am\nt ( dec5t]+1 ! rule be+ t e c5timet] ( displacem5t causes z _m prism diopt]s z !re are diopt]s 9 t m]idian ( ! l5s4 ,?us #a sph]e1 or cyl9d] axis #ij1 dec5t]$ "o c5timet] outw>d1 is equival5t to add+ a "o degree prism diopt] l5s1 base out4 ,,de/rophoria ,,& ,,laevophoria ,^! are t]ms d5ot+ a condition 9 :i* bo? eyes are capable ( abnormal rotat+ t[>d ! "r or left1 z ! case may be4 ,! movem5t 9 ! opposite direction is mo/ common4 ,! pati5t c (t5 rotate 8 eyes #fj degrees t[>d ! "r1 & to p]haps only #dj degrees to ! left4 ,8 position ( re/ is p>allel ) 8 visual l9es1 b to ! "r1 9 look+ at objects directly 9 front1 he is mu* m com=table ) 8 head turn$ slightly to ! left4 ,x is difficult to acc\nt =1 except on ! !ory t def9ite movem5t ( ! eyes is r to ! "r ?an to ! left 9 mo/ occupations4 ,! position ( ! pap] 9 writ+ at a desk t5ds t[>d dextrophoria2 9 read+1 we move our eyes /eadily f left to "r & !n beg9 a new l9e by a s+le brief movem5t to ! left2 ! ?+s t a man uses mo/--:e!r he be labor] or /ud5t--are kept )9 rea* ( ! "r h&1 & 9 ref]r+ to !m ! eyes are con/antly turn$ t[>d ! "r4 ,h[ev]1 :5 ^! conditions result f o!r imbalances1 !y mu/ be treat$ m c>efully4 ,= in/ance1 a pati5t ^: "r int]nus is p>alys$ or cong5itally defective on look+ to ! left1 has a cross diplopia :i* vani%es to ! "r2 z a result1 he soon assumes a habit ( c>ry+ 8 head 9 ?is position4 ,ord9>ily1 ?is w cause no discom=t2 b if ! left int]nus is s weak t x _c foll[ ! "r ext]nus to its position ( greate/ ease1 ! visual l9es are evid5tly diff]5t & ! case mu/ be treat$ z an exophoria4 ,if1 on ! o!r h&1 ! left int]nus ov]-balances ! "r ext]nus1 ! condition is an esophoria & mu/ be treat$ z su*4 ,simil> reason+ applies to ! conditions kn[n z ,anaphoria & ,kataphoria1 9 :i* ! visual l9es are p>allel to ea* o!r b direct$ up or d[n ) reg>d to ! horizontal plane ( ! body4 ,9 ! fir/1 ow+ to cong5ital abnormalities1 ! eyes usually t5d upw>d & ! individual mu/ g ab\t ) 8 *9 on 8 *e/1 s t 8 eyes may look 9 front & yet rema9 9 ! position ( re/4 ,9 ! second1 ! *9 is held 9 ! air & ! body ar*$ backw>d4 ,b1 unless extreme1 nei!r ( ^! conditions causes m ?an cosmetic difficulty & bo? %\ld be undi/urb$ ow+ to ! extreme difficulty ( secur+ ! same op]ative effect on bo? eyes4 ,suitable prisms are mu* m likely to be b5eficial4 ,illu/ration3 ,supports = ,hold+ ,! ,ski-optomet] ,floor ,/& ,illu/ration3 ,wall ,bracket ,illu/ration3 ,*air ,clamp ,illu/ration3 ,*air ,atta*m5t ) ,upright ,*oice may be made f any ( ! above4 ,! ,wall ,bracket is recomm5d$1 unless refractioni/ is provid$ ) a speciali/'s *air1 to :i* ! ,*air ,atta*m5t ) ,upright may be atta*$4