天津职业大学 文本 The Binocular Accommodative Response in Uncorrected Ametropia_眼屈光学

144燃州I1CL7核0I模.7-通 C101室r4N:pkNg33线3 h●2ln可O ORIGINAL ARTICLE The Binocular Accommodative Response in Uncorrected Ametropia MITSUO TSUKAMOTO,MD,TAKAYUKI NAKAJIMA,MD,JUNKO NISHINO,MD, YOSHIAKI HARA,MD,HIROSHI UOZATO,MD,and MOTOTSUGU SAISHIN,MD Depare sfOpirbiwoiagy.Non Mdical Unisenay.Nand.apa ABSTRACT:Purpose.To measure the changes in astigmatism and in the degree of anisumetrupia when ametropes respond to accommodative stimulation.Merhods.The accommodative responses of ametropes were binocularly measured with an improved photorefractometer (PR-1100),which objectively measured binocular refraction in all meridians simultaneously,when a visual fivation target was shown in natural space at 5 and 0.5 m.Resulfs (1)Changes of astigmatism and anisometropia occur during binocular accommudation.(2)Changes of astigmatism mainly result from Lag of accommodation in the borizontal meridian.(3)Changes of anisometropia result from the effort to focus. (4)The interaction of both eyes is suggested as the cause of the changes of astigmatism and anisometropia with accommodation.(5)In the majority of strong anisometropes (nonoverlapping group in this paper),the magnitude of anisometropia decreases (approaching isometropia)with accommodation.Conclusion.Changes in astigmatism and anisometropia can occur during accommodation,and these interactions of hoth cyes with accommodation may contribute to the development and maintenance of binocular function.(Optum Vis Sci 2001;78:763-768) Key Words accommodation,astigmatism,anisometropia,binocular interaction,binocular visin uring an investigitian with a Canon R-1 autorefractor,we simulrancously.Dichroic mirors were added for this cxperiment leamed that the fuctuaron ptterns efaccommotive to present an accommodative stimulation target on the instr- sponse.which changed from moment to momen.were in ment's opical axis.The emor caued by a subject's convergence. Huenord by duing the fillenw ry.Thencfom,we:ampermod that a which rrsnlts in a svial ix heing nonuineidkental wirh commodrive nopons during hinocubr acmmodtion dpndod the oprical axis of the PR-1100,was evaksted by oxmputer simu- on the interaction of one eye's refraction with its ellow eye's refrac- lation as peoducing 0.18 D apainst-the-rule astigmacism.This is tion.-However,we had omeansofverifving this phenomenon.By dercribed in detail ina previous paper. improving th:PR-1100 mfuact:mener,the moxsrcling of the binosulr ccmmodive repome bece posible,s indicaed inpevious Subjects paper."In that paper,we sporod that the meity ofhileral em- metropes showed with-the-rule astigatis and lag ofaccmmoda- The abjects were slected from a goup of 2486 clementary, tinn in the harznntal meriliin with acrommedaton. junior high.high school,and women's university srodents,aged In this paper.we report dropes.In binocarcom from 12 in 26 years.Of this mntal,259 wzr sdectad for h-ning modation,chainpes of astigmatism conribute m changes in the leat [0V20)beit-comecred visul acairy,otbophora,orml magnirude fanometropia.This might contribue to the devel- binocular function,intact ocular media,and intact oodar fundus. opment and maintennce of hineealr visian. The pro for the subjects was described in a previus paper. Fmom the 259 sibjech,15 suhjats with hinnctlar emmrtropi were excluded (subjects from the prevous paper).and for y sub MATERIALS AND METHODS jects,there was insafficient data The mmaining 235 studkents with Instrument amtmopia are the subects of this puaper. We mad an impnwved PR-1100 pheran-frctommeter for thise- Measurement periment.The PR-1100 was developed using the principle ofpho torcfraction"and introducing a diffuse Fight source and a knis When the subjects were instructed to fix their eyes on the target egeo measure binocular refraction objectvy inal meridians (having a visual angk af 1)placed at5 m.thresiv Oproemy end Viuor Semee.Vol /bNa.10.Oesber

ORIGINAL ARTICLE The Binocular Accommodative Response in Uncorrected Ametropia MITSUO TSUKAMOTO, MD, TAKAYUKI NAKAJIMA, MD, JUNKO NISHINO, MD, YOSHIAKI HARA, MD, HIROSHI UOZATO, MD, and MOTOTSUGU SAISHIN, MD Department of Ophthalmology, Nara Medical University, Nara, Japan ABSTRACT: Purpose. To measure the changes in astigmatism and in the degree of anisometropia when ametropes respond to accommodative stimulation. Methods. The accommodative responses of ametropes were binocularly measured with an improved photorefractometer (PR-1100), which objectively measured binocular refraction in all meridians simultaneously, when a visual fixation target was shown in natural space at 5 and 0.5 m. Results. (1) Changes of astigmatism and anisometropia occur during binocular accommodation. (2) Changes of astigmatism mainly result from lag of accommodation in the horizontal meridian. (3) Changes of anisometropia result from the effort to focus. (4) The interaction of both eyes is suggested as the cause of the changes of astigmatism and anisometropia with accommodation. (5) In the majority of strong anisometropes (nonoverlapping group in this paper), the magnitude of anisometropia decreases (approaching isometropia) with accommodation. Conclusion. Changes in astigmatism and anisometropia can occur during accommodation, and these interactions of both eyes with accommodation may contribute to the development and maintenance of binocular function. (Optom Vis Sci 2001;78:763–768) Key Words: accommodation, astigmatism, anisometropia, binocular interaction, binocular vision During an investigation with a Canon R-1 autorefractor, we learned that the fluctuation patterns of accommodative re￾sponse, which changed from moment to moment, were in￾fluenced by closing the fellow eye. Therefore, we suspected that ac￾commodative response during binocular accommodation depended on the interaction of one eye’s refraction with its fellow eye’s refrac￾tion.1–7 However, we had no means of verifying this phenomenon. By improving the PR-1100 refractometer, the recording of the binocular accommodative response became possible, as indicated in a previous paper.8 In that paper, we reported that the majority of bilateral em￾metropes showed with-the-rule astigmatism and lag of accommoda￾tion in the horizontal meridian with accommodation. In this paper, we report data for ametropes. In binocular accom￾modation, changes of astigmatism contribute to changes in the magnitude of anisometropia. This might contribute to the devel￾opment and maintenance of binocular vision. MATERIALS AND METHODS Instrument We used an improved PR-1100 photorefractometer for this ex￾periment. The PR-1100 was developed using the principle of pho￾torefraction9 and introducing a diffuse light source and a knife￾edge to measure binocular refraction objectively in all meridians simultaneously. Dichroic mirrors were added for this experiment to present an accommodative stimulation target on the instru￾ment’s optical axis. The error caused by a subject’s convergence, which results in a subject’s visual axis being noncoincidental with the optical axis of the PR-1100, was evaluated by computer simu￾lation as producing 0.18 D against-the-rule astigmatism. This is described in detail in a previous paper.8 Subjects The subjects were selected from a group of 2486 elementary, junior high, high school, and women’s university students, aged from 12 to 26 years. Of this total, 259 were selected for having at least 5/5 (20/20) best-corrected visual acuity, orthophoria, normal binocular function, intact ocular media, and intact ocular fundus. The protocol for the subjects was described in a previous paper.8 From the 259 subjects, 15 subjects with binocular emmetropia were excluded (subjects from the previous paper), and for 9 sub￾jects, there was insufficient data. The remaining 235 students with ametropia are the subjects of this paper. Measurement When the subjects were instructed to fix their eyes on the target (having a visual angle of 10°) placed at 5 m, three consecutive 1040-5488/01/7810-0763/0 VOL. 78, NO. 10, PP. 763–768 OPTOMETRY AND VISION SCIENCE Copyright © 2001 American Academy of Optometry Optometry and Vision Science, Vol. 78, No. 10, October 2001

764 Accommodation in Uncorrected Ametropia-Tsukamoto et al. mcasurements were taken with the improved PR-1100.Then the tion in the vertical meridian.In this oquation,with-the-rule astig- target was changed to a distance of 0.5 m (having a visual angle of matism is expresd as positive value,and aginst-the-rule astig 10),and again the three measurements were taken.As the targets, matism is expressed as negative values. stuffed beary (a three-dimensioeal target)of a popular Japuanese cartoon character were used.In our previous stdies,we found that this three-dimensional target cld produoe accmmodarive n Degree of Anisometropia spons pattems with rdatinvely minoe fluctutionscumpard witha In the stric meaning of isometropia the retinal conjugate poincs af fashlight oa Landolt ring (a t-dimensional target) boch eves'mutual cocrepooding principal meridians e the same. Thus most of the subjects have some degree of anisometropia.To Classification of Subjects express the mnide ofaniomoboth with and without tpmtism.we pow introduce a new inder of anisometropi s the Based on refraction for the 5m target.the subjects were divided oonept of the rpping of both eyesic intervals (interval into three categories:ourside,intersect,and inside.The ourside of Sturm in Fig.2)in an optical object space and name it"degree of subjects were defined as those with all their retinal conjugare anismtrupia"Overapping aresr expresed by plus diopers.In points FI and F2 (as shown in Fig.1)of boch righs and lft the case of no overlap,the nonowerlpping are is expresed by minus eyes,lcated farther than 0.5 m (corresponding to the accommo dopeers(Fig,3).Thus,true smeopi would be expressed ase datie stimulus in this paper).The inside subject had Fl and F2 of and positive and nogive valucs cpres lw and high magnitude of boch cyo ncarcr than the 0.5 m.Other subjoots were catcgorined as anicomctrupia,rspoctidy. the intersce group wh rtinal oonjugate points were both far In intruduing the dognx of anismropia.al sbjccts were ther and nearer than or cxactly at 0.5 m. diviked into cither anoverapping group"or a"nonowerlpping group."as shown in Fig.3.The subjects with a zero value when Astigmatism focusing ar 5 m,the stricr meaning of isometropia.were included in the overlapping goup,and cach e of ster isomerropi was Typically,with-the-rule astigmatism,against-the-rle astiga- plotted on the horirontal oe vertical aesin all six graphs in Fig.4. tism,and oblique aigmarism are defined as having the greatest refractive power berween 6 and 120;between and 30 c RESULTS between 150and 180";and berween 30 and GO or between 120 and 150.respectively.2Of the subjects studied,only a few per The ourside subjects (N 109.range of refraction,+333 to cent had oblique astigmatism.Therefore,we classified the sabjects -1.92 D:mean+SD.-0.69 0.8 D)were subdivided into an with-the-rule or against-the-rul accoeding to whether their overlapping Broup IN=70:mean degree ofanisometropia,+0.29 greatet power lay closer to 90"or 180'. D;range,0 to +2.75 D):and a nonoverlapping group (N -39 The degree of astigmatism was cakulated using an equation that mcan degree of anisometropia,-0.78 D:range,-0.08 to -3.17 suberacts the refraction in the borizontal meridian from the refrac- D).The intersect subjects (N -92:range.+2.33 to -7.50 Dp mean SD,-1.93 1.17 D)were subdivided into an overlap- ping group (N-12:mean degree of anisometropi.+0.56 D: F2 F1 an,0t+1.83D功：and a monowerlapping group (N=80:man degnoe of anisomctropis -1.33 D;rangs,-0.08 to -3.58 D). Eularle 轻相 Thc inside subjects (N 34:rang,-2.00 to -4.75 D;mcan SD,-3.020.68 D)were subdivided into an overlapping group (N -15;mean degroc of anisomctropia,+0.11 D:rang&s 0 to 器 +042 D):and a nomoverlipping group (N=19:mean degree of anisametropia.-0.58 D:range,-0.08 to -1.58 D).The vari- Irt网s ances in the set of three mfractioers for each subject showed no significane differes amng the abowe sis groups (analysis of varianee,p (1.659). D ■ 9 ng均 今 H aem中日d1n 1公：iiGi0fe1 L FIGURE 1. lhc率ee两ifed into thmse categnri:0 itside,interect aed imide subjects.The ouside subjects wese detned as those wich all their nenal rerjuzane peints F1 and F2 of hoth right and le wyes,located FIGURE 2. farther than 0_5 m (oomresponding to the accommodative simulus in ths Resinal conjugate points of an eye.The distance between FI tinal paper).The imsice subjicts had their F1 and F2 ef bot eyins rwaner than conjugate poire in frst principual meridfin)and F2 tinal cnnj-yyale paict 0.5 m.The imersect group had retinal conugate points that were both in second principal merid ani is defined as the interval of Soum in the farthur and nnr thun o vxactly 0.5 m. image outu o te arye's otical wpbem. Optemverry ad Vuien Scierer.VaL 78.Na.10.Octobe 2001

measurements were taken with the improved PR-1100. Then the target was changed to a distance of 0.5 m (having a visual angle of 10°), and again the three measurements were taken. As the targets, stuffed bears (a three-dimensional target) of a popular Japanese cartoon character were used. In our previous studies, we found that this three-dimensional target could produce accommodative re￾sponse patterns with relatively minor fluctuations compared with a flashlight or a Landolt ring (a two-dimensional target).1–7 Classification of Subjects Based on refraction for the 5-m target, the subjects were divided into three categories: outside, intersect, and inside. The outside subjects were defined as those with all their retinal conjugate points,10, 11 F1 and F2 (as shown in Fig. 1) of both right and left eyes, located farther than 0.5 m (corresponding to the accommo￾dative stimulus in this paper). The inside subjects had F1 and F2 of both eyes nearer than the 0.5 m. Other subjects were categorized as the intersect group, whose retinal conjugate points were both far￾ther and nearer than or exactly at 0.5 m. Astigmatism Typically, with-the-rule astigmatism, against-the-rule astigma￾tism, and oblique astigmatism are defined as having the greatest refractive power between 60° and 120°; between 0° and 30° or between 150° and 180°; and between 30° and 60° or between 120° and 150°; respectively.12 Of the subjects studied, only a few per￾cent had oblique astigmatism. Therefore, we classified the subjects as with-the-rule or against-the-rule according to whether their greatest power lay closer to 90° or 180°. The degree of astigmatism was calculated using an equation that subtracts the refraction in the horizontal meridian from the refrac￾tion in the vertical meridian. In this equation, with-the-rule astig￾matism is expressed as positive values, and against-the-rule astig￾matism is expressed as negative values. Degree of Anisometropia In the strict meaning of isometropia, the retinal conjugate points of both eyes’ mutual corresponding principal meridians are the same. Thus most of the subjects have some degree of anisometropia. To express the magnitude of anisometropia13, 14 both with and without astigmatism, we now introduce a new index of anisometropia as the concept of the overlapping of both eyes’ astigmatic intervals (interval of Sturm in Fig. 2) in an optical object space and name it “degree of anisometropia.” Overlapping areas are expressed by plus diopters. In the case of no overlap, the nonoverlapping area is expressed by minus diopters (Fig. 3). Thus, true isometropia would be expressed as zero, and positive and negative values express low and high magnitude of anisometropia, respectively. In introducing the degree of anisometropia, all subjects were divided into either an “overlapping group” or a “nonoverlapping group,” as shown in Fig. 3. The subjects with a zero value when focusing at 5 m, the strict meaning of isometropia, were included in the overlapping group, and each case of strict isometropia was plotted on the horizontal or vertical axes in all six graphs in Fig. 4. RESULTS The outside subjects (N
109; range of refraction, 3.33 to 1.92 D; mean  SD, 0.69  0.84 D) were subdivided into an overlapping group (N
70; mean degree of anisometropia, 0.29 D; range, 0 to 2.75 D); and a nonoverlapping group (N
39; mean degree of anisometropia, 0.78 D; range, 0.08 to 3.17 D). The intersect subjects (N
92; range, 2.33 to 7.50 D; mean  SD, 1.93  1.17 D) were subdivided into an overlap￾ping group (N
12; mean degree of anisometropia, 0.56 D; range, 0 to 1.83 D); and a nonoverlapping group (N
80; mean degree of anisometropia, 1.33 D; range, 0.08 to 3.58 D). The inside subjects (N
34; range, 2.00 to 4.75 D; mean  SD, 3.02  0.68 D) were subdivided into an overlapping group (N
15; mean degree of anisometropia, 0.11 D; range, 0 to 0.42 D); and a nonoverlapping group (N
19; mean degree of anisometropia, 0.58 D; range, 0.08 to 1.58 D). The vari￾ances in the set of three refractions for each subject showed no significant differences among the above six groups (analysis of variance, p
0.659). FIGURE 1. Classification of subjects. According to the data taken when fixing at 5 m, all subjects were classified into three categories: outside, intersect, and inside subjects. The outside subjects were defined as those with all their retinal conjugate points, F1 and F2 of both right and left eyes, located farther than 0.5 m (corresponding to the accommodative stimulus in this paper). The inside subjects had their F1 and F2 of both eyes nearer than 0.5 m. The intersect group had retinal conjugate points that were both farther and nearer than or exactly at 0.5 m. FIGURE 2. Retinal conjugate points of an eye. The distance between F1 (retinal conjugate point in first principal meridian) and F2 (retinal conjugate point in second principal meridian) is defined as the interval of Sturm in the image space of the eye’s optical system. 764 Accommodation in Uncorrected Ametropia—Tsukamoto et al. Optometry and Vision Science, Vol. 78, No. 10, October 2001

Accommodation in Uncomected Ametropia-Tsukamoto et al.765 Ovorbpping group 51 Overlapping group N0-/度a馆99p 4 (+ Gp可小r网 Non-overlapping g'eup 用 FIGURE 3. 2 Deaoe of aniomctropia.The overlpped inervak od Stum of Loth the nipet and left eyes are expressed hy a posive doptnc vale.These s.bjects belang to the overlapping group.In this expression.a stict *200 i时mpi表pnmsed as a7 m value Neresarily.the nther ahjerts with dear distarce between one eye's F1 and the fellow eve's F2 are dauified as the nonowerlapping group.The distance is espnased by a +30 negathe d optric value. When thesc abjccts ficnod on the 05-m target,thcir nfractions man±SLU》wtr5 folknws:the ourside abpcct事wd-1.33士 0.66D in theborizuontal and -1.96 0.57 D in thevertical meridin in the uverapping group and -1.060.97 D in the horicontal and -1.79 0.96 D in the vertical meridian in the nonoverlpping group.The intersect subjects showed -1601.10 D in the hori rval and-2.74±087D的the vertical meridun in the averap FIGURE 4. pinggroup and -1.95 1.12D)in the hortrontaland-2.76+0.96 D in the verrical meridin in the nonovrapping gmup.The insidk ￥xa%p两satk率nlt,nd inside subgct书.n horiznt suhjcrrs showed-262±0,87 in thehorizontaland-3Dz±0,63 rows and overlapping and nonoverfapping groups in vertical columns.In Din theverical meridan in theovrlappinggroup and-2750.90 ch zraph,the ahscisa and crdina expns clepree nf aninmetmpi (n diopters when a fiaton target was presemed at 5 and 0.5 m respec. D in the horiontal neridian and -3.110.74 D in the verical tively.The pooitive anu shews tnrlapgsod clegree,and the nogative an meridian in the nonoverapping group.Berween the hoizoncl and shows nonoverlapped degree.The three percentages fram top to botom the vertica meridians all grouped subjeces had sratisrical differences in the upper tighl corner of eath grigh shonw the putertru c subjeu (paired -s,p foe all).Therefoee,in theounsidesubjects,lag phed3be,cn.ndb8ow中e45°Ine,rep6 cthvely. of acccmmodtion distinetly occured in the horooetal meridian.Foe darifying inside sbjects'behnior.two way anahsis of variance wis icant ditferencesgm value (degrees with kinds:with the rule used on the three measurements berween focusing at 5 m and 0.5 m in and gainst the rule)between focusing on the 5 m target and focusing each horiontal and vertical meridian.Staristical differences were on the0.5 m target were found for the overlapping group of outside found berween foousingt 5 m and focusing at 0.5 m on both hori subjects (p001)and in all nonoverlapping groups (pfo xoocal (p0001)and vertical (p0.001)meridians all groups),bat not for the intersect (p 0.178)and inside (p Basod on the data frum nefractions,the changes of astigmacism 0.056)guups in the overapping groups with the paircd frum focusing on the 5-m tarpet to foousing on the 0.5-m targt were The degrve of anisometropia when subjects focused on the s follo:the ouside sbjoct市owed the change from+03约D 0.5-m target were as follows:in the outside subjects,the mean (rg,-l.00o+2.92D)o+063D(anw,-1.00o2.75D)in anisometropia changed frum +0.29 D (focusing at 5 m.described the overlapping group.and from +0.15 D (range,-0.50 to +2.25 above)to +0.42 0.62 D and from -0.78 to +0.101.12 D in D)0 +0.73 D (rang,-0.58 to +3.17 D)in the nonowerlpping the nverlspping group and the nonowverlapping gromps,respee groop.The intere subjects shownd a ching from +094D(rang, tively.In the intenat xuhjeets,it changed from +0.56D ta +0.40 -1,42 to +3.25 D)to+1.14 D (rarg;-0.83 to +4.50 D)in the ±097 D and from-1,33Dto-0,44±1.10 D in the overhp overapping grop,and frum +0.29 D(rangs,-1.00 to +3.75 D)to ping group and the nonoverlapping groups,respecticly.In the +0.81 D (rang,-0.50 o +2.58 D)in the nonowrlapping group. inside subjccrs,it chargxd frum +0.11 D to +0.03 0.53 D and The inside subjects showed a change from +0.21 D(nege.-0.3 t0 iom-0.58Do-0.36±a.84 Din the overlapping影opnd +1.08 D)to +01.n D(range,-0).33 10 +1.50 D)in the overlapping the monoverlapping goups,respectively.The difference in the de- groop,and fromn 0D (range.-01.58 to +0.58 D)to +0.35 D (range, gree of anisomerropia berween focusing at S and D.S m was statis- -l.7乃o+1.7乃D)in the nee山pping goup Statistically signif tically significant in theouteide(p <0.001)and the interseet (p<

When these subjects focused on the 0.5-m target, their refractions (mean  SD) were as follows: the outside subjects showed 1.33  0.66 D in the horizontal and 1.96  0.57 D in the vertical meridian in the overlapping group and 1.06  0.97 D in the horizontal and 1.79  0.96 D in the vertical meridian in the nonoverlapping group. The intersect subjects showed 1.60  1.10 D in the hori￾zontal and 2.74  0.87 D in the vertical meridian in the overlap￾ping group and 1.95  1.12 D in the horizontal and 2.76  0.96 D in the vertical meridian in the nonoverlapping group. The inside subjects showed2.620.87 D in the horizontal and3.020.63 D in the vertical meridian in the overlapping group and2.750.90 D in the horizontal meridian and 3.11  0.74 D in the vertical meridian in the nonoverlapping group. Between the horizontal and the vertical meridians, all grouped subjects had statistical differences (paired t-test, p  0.001 for all). Therefore, in the outside subjects, lag of accommodation distinctly occurred in the horizontal meridian. For clarifying inside subjects’ behavior, two-way analysis of variance was used on the three measurements between focusing at 5 m and 0.5 m in each horizontal and vertical meridian. Statistical differences were found between focusing at 5 m and focusing at 0.5 m on both hori￾zontal (p  0.001) and vertical (p  0.001) meridians. Based on the data from refractions, the changes of astigmatism from focusing on the 5-m target to focusing on the 0.5-m target were as follows: the outside subjects showed the change from 0.39 D (range, 1.00 to 2.92 D) to 0.63 D (range, 1.00 to 2.75 D) in the overlapping group, and from 0.15 D (range, 0.50 to 2.25 D) to 0.73 D (range, 0.58 to 3.17 D) in the nonoverlapping group. The intersect subjects showed a change from 0.94 D (range, 1.42 to 3.25 D) to 1.14 D (range, 0.83 to 4.50 D) in the overlapping group, and from 0.29 D (range, 1.00 to 3.75 D) to 0.81 D (range, 0.50 to 2.58 D) in the nonoverlapping group. The inside subjects showed a change from 0.21 D (range, 0.33 to 1.08 D) to 0.40 D (range, 0.33 to 1.50 D) in the overlapping group, and from 0 D (range, 0.58 to 0.58 D) to 0.35 D (range, 0.75 to 1.75 D) in the nonoverlapping group. Statistically signif￾icant differences in astigmatic value (degrees with kinds: with-the-rule and against-the-rule) between focusing on the 5-m target and focusing on the 0.5-m target were found for the overlapping group of outside subjects (p  0.001) and in all nonoverlapping groups (p  0.001 for all groups), but not for the intersect (p
0.178) and inside (p
0.056) groups in the overlapping groups with the paired t-test. The degree of anisometropia when subjects focused on the 0.5-m target were as follows: in the outside subjects, the mean anisometropia changed from 0.29 D (focusing at 5 m, described above) to 0.42  0.62 D and from 0.78 to 0.10  1.12 D in the overlapping group and the nonoverlapping groups, respec￾tively. In the intersect subjects, it changed from 0.56 D to 0.40  0.97 D and from 1.33 D to 0.44  1.10 D in the overlap￾ping group and the nonoverlapping groups, respectively. In the inside subjects, it changed from 0.11 D to 0.03  0.53 D and from 0.58 D to 0.36  0.84 D in the overlapping group and the nonoverlapping groups, respectively. The difference in the de￾gree of anisometropia between focusing at 5 and 0.5 m was statis￾tically significant in the outside (p  0.001) and the intersect (p  FIGURE 3. Degree of anisometropia. The overlapped intervals of Sturm of both the right and left eyes are expressed by a positive dioptric value. These subjects belong to the overlapping group. In this expression, a strict isometropia is expressed as a zero value. Necessarily, the other subjects with clear distance between one eye’s F1 and the fellow eye’s F2 are classified as the nonoverlapping group. The distance is expressed by a negative dioptric value. FIGURE 4. Changing degree of anisometropia between focusing at 5 m and at 0.5 m. Six graphs express outside, intersect, and inside subjects in horizontal rows and overlapping and nonoverlapping groups in vertical columns. In each graph, the abscissa and ordinate express degree of anisometropia (in diopters) when a fixation target was presented at 5 and 0.5 m, respec￾tively. The positive area shows overlapped degree, and the negative area shows nonoverlapped degree. The three percentages from top to bottom in the upper right corner of each graph show the percentage of subjects plotted above, on, and below the 45° line, respectively. Accommodation in Uncorrected Ametropia—Tsukamoto et al. 765 Optometry and Vision Science, Vol. 78, No. 10, October 2001

766 Accommudalion in Uncorrected Ametrupia-Tsukamoto et al. 0.001)subjects of the nonoverlapping group (paired ttest).The the rule astigmatism changes to with the ruk timatisme and in the differences were noc significant for the other groups (p-0.089. third guadrant.sint the rule istipmatism decreases as a result of 0.560.0.628.and 0.157 for outside,incersect,and inside subjects more sccomnodative response (change of refraction)in the vertical of the owurlapping and inside subiccts of the nonoverlapping mcridians than in the horizntal mcridlians.The danta shown bckw th groupe,repecrively). 43"line rpnxent a doorce in the amount of with-the-ruk astigma- Thee findings are summarioed in Fig.4 and 5.The changes of tism,that is to sy,an increabe in against-the-rul astigmatism.More astigmatism (Fig 5)and the degree of anisomnctrupia (Fig 4)berween specifically,in the fint qudrant.with-the-rule astigmtism simply focusing5 m on the abociss)and focsing吧ta.5 m (on the ord击 docein the third quadrans,against-the-ruk asigmati incres nate)ar pletted foe ech of the overapping and nonowerlpping e;and in the fotarth qutadramnt,with-the-mile asigmitim tums inm gropsof the ouide,intereet,and insidesuhjos The dat pointsan ain-the-nile astigmatism as a rrsult of mcer accommoditive n the45"line show nochang in amount ofthevales between fixsing sponse (changs of nfraction)in the horianneal meridans than in the the 5-m targx and fcusingat the 05-m tangst In Fig 5,the points vrtical mcrklians. abowe the 45"line show an inircase in the amount of with-the-rk For the ounsice subjcets,63%of the onerapping gruup fell astigmatism.More specifically.in the first quadrant.with-the- above the i5"Line.6%on the line,and 31%below the line.The rule astigmaism simply increase&in the second quadrant.aginst- monowerlapping group had 68%above the i line.10%on the line,and 22%below the line.Appeoximately rwo-thinds af boch the overlpping group and the nonoverlpping group were above Cverapoing group Non-overlappng group the 45"line,and one-third was below the line.In terms of the change of asigmatism with accommodation (referring to which meridian shows stronger refractive change berween the two prin cipal meridians).isty.the overlapping group and the non ovesapping aroup in the ourside subjecs were dassified in the same carepory (p=0.256.xtest).Intersect subjects showed 58 and 77%6 abuve the 45"line,4%and 4%on the linc,and 38%and 19%bdow the line in the overlapping group and the nonoverlap- ping group,respectively.Their satistical independence was subdle a品 iM1G湘 3+4e (p-0.011.x test).Inside subjecrs sbowed 57%and 55%ahove Imersec sucjecl the 45 line.17%6 and 21%on the line,and 27%and 24%below +40 the line in the overbpping gruup and the noneverlapping gromp. ropectively.They were noe statistically different (p =0.730,X test).Outside subiccts and interocet subjects were not statistically different in the uverlapping gruup (p-0.517,x'test)and in the nonowerlapping group (p-0.187,x'test).On the contrary,the inside subjects in both the overlpping group (p-0007.x'test) and the noncwerlpping group (p =00004.X test)were seatisti- cally different fromn the outside and the interseet subjects. la格 340 In terms of the degree of anisometropea,there were marked difter- eners hetween the cnerlpping and the nonorrlpping gromps in all three daifed shjeene outde,interect,and inside.In the overap- ping groupthe ratio of subjects increngor decreing in the depree P of anisometropa in the ourside and the incersect subjects was almost 50.50.There ws an increase of i6%and a decrease of 50%in the ouride subjects and an increase of 509i ad a decrease of 5u in the instersect subrects.Subjects with nochange made upoely 4 ofthe outside subjocts and none of the intersecr subjects. 1 Conversely,in the nonowerlapping group.>80%of the subjects in both the outside and the intersect groups had an increase in the turgH st 0.5m lsrgel aǜ5m magnitude of overlap:82%of the ourside and 87%of the intersect subjects.Only 13%of the outside and 10%of the intersect sub FIGURE 5. jects shuwed a docrcase in the magnitudc ofoverap.Thasc with no expeess the o.tside.inoersect,and inside s.bjects in horizontal rows and change made up 5%of the autside and 3%of theineencct subjoct. the ovurlapping and nonverlapping gops in vrtical columm.In wuch 'This markodly diffcrent tendency in the charge of the degroe of graph the ahscissa and te ordirate express astigmatism value lin dopt anisomctropia on accommodation between the overlapping group when a ficatiun largt wirs pnommludd al 5 and 05 m nopxtividy.The and the nopoverlapping group was also obeerved in the inside postive a'ea shows with.the-rue asipmansm.and the neganve area shuw aguiol-the-nule plisnalist The tocuniud!dau on the xdle ul ocmu subjects.Of the overlapping group.3 showed an increase,20 indcates no astipmatism.The theee percectages tom top to hottom in showed no change,and 47%showed a decreae:and of the nan- owerlapping groap.63%shewed an inerease.5%showed no ahove,on,and hekw the 45 Ine,tespectively change,and 32%showed a decreasc.In vicw ofstaristios,therefore

0.001) subjects of the nonoverlapping group (paired t-test). The differences were not significant for the other groups (p
0.089, 0.560, 0.628, and 0.157 for outside, intersect, and inside subjects of the overlapping and inside subjects of the nonoverlapping groups, respectively). These findings are summarized in Figs. 4 and 5. The changes of astigmatism (Fig. 5) and the degree of anisometropia (Fig. 4) between focusing at 5 m (on the abscissa) and focusing at 0.5 m (on the ordi￾nate) are plotted for each of the overlapping and nonoverlapping groups of the outside, intersect, and inside subjects. The data points on the 45°line show no change in amount of the values between focusing at the 5-m target and focusing at the 0.5-m target. In Fig. 5, the points above the 45° line show an increase in the amount of with-the-rule astigmatism. More specifically, in the first quadrant, with-the￾rule astigmatism simply increases; in the second quadrant, against￾the-rule astigmatism changes to with-the-rule astigmatism; and in the third quadrant, against-the-rule astigmatism decreases as a result of more accommodative response (change of refraction) in the vertical meridians than in the horizontal meridians. The data shown below the 45° line represent a decrease in the amount of with-the-rule astigma￾tism, that is to say, an increase in against-the-rule astigmatism. More specifically, in the first quadrant, with-the-rule astigmatism simply decreases; in the third quadrant, against-the-rule astigmatism increas￾es; and in the fourth quadrant, with-the-rule astigmatism turns into against-the-rule astigmatism as a result of more accommodative re￾sponse (change of refraction) in the horizontal meridians than in the vertical meridians. For the outside subjects, 63% of the overlapping group fell above the 45° line, 6% on the line, and 31% below the line. The nonoverlapping group had 68% above the 45° line, 10% on the line, and 22% below the line. Approximately two-thirds of both the overlapping group and the nonoverlapping group were above the 45° line, and one-third was below the line. In terms of the change of astigmatism with accommodation (referring to which meridian shows stronger refractive change between the two prin￾cipal meridians), statistically, the overlapping group and the non￾overlapping group in the outside subjects were classified in the same category (p
0.256, 2 test). Intersect subjects showed 58% and 77% above the 45° line, 4% and 4% on the line, and 38% and 19% below the line in the overlapping group and the nonoverlap￾ping group, respectively. Their statistical independence was subtle (p
0.011, 2 test). Inside subjects showed 57% and 55% above the 45° line, 17% and 21% on the line, and 27% and 24% below the line in the overlapping group and the nonoverlapping group, respectively. They were not statistically different (p
0.730, 2 test). Outside subjects and intersect subjects were not statistically different in the overlapping group (p
0.517, 2 test) and in the nonoverlapping group (p
0.187, 2 test). On the contrary, the inside subjects in both the overlapping group (p
0.007, 2 test) and the nonoverlapping group (p
0.0004, 2 test) were statisti￾cally different from the outside and the intersect subjects. In terms of the degree of anisometropia, there were marked differ￾ences between the overlapping and the nonoverlapping groups in all three classified subjects: outside, intersect, and inside. In the overlap￾ping group, the ratio of subjects increasing or decreasing in the degree of anisometropia in the outside and the intersect subjects was almost 50:50. There was an increase of 46% and a decrease of 50% in the outside subjects and an increase of 50% and a decrease of 50% in the intersect subjects. Subjects with no change made up only 4% of the outside subjects and none of the intersect subjects. Conversely, in the nonoverlapping group, 80% of the subjects in both the outside and the intersect groups had an increase in the magnitude of overlap: 82% of the outside and 87% of the intersect subjects. Only 13% of the outside and 10% of the intersect sub￾jects showed a decrease in the magnitude of overlap. Those with no change made up 5% of the outside and 3% of the intersect subjects. This markedly different tendency in the change of the degree of anisometropia on accommodation between the overlapping group and the nonoverlapping group was also observed in the inside subjects. Of the overlapping group, 33% showed an increase, 20% showed no change, and 47% showed a decrease; and of the non￾overlapping group, 63% showed an increase, 5% showed no change, and 32% showed a decrease. In view of statistics, therefore, FIGURE 5. Changes of astigmatism between focusing at 5 m and at 0.5 m. Six graphs express the outside, intersect, and inside subjects in horizontal rows and the overlapping and nonoverlapping groups in vertical columns. In each graph, the abscissa and the ordinate express astigmatism value (in diopt￾ers) when a fixation target was presented at 5 and 0.5 m, respectively. The positive area shows with-the-rule astigmatism, and the negative area shows against-the-rule astigmatism. The recorded data on the scale of zero indicates no astigmatism. The three percentages from top to bottom in each graph’s upper right corner show the percentage of eyes plotted above, on, and below the 45° line, respectively. 766 Accommodation in Uncorrected Ametropia—Tsukamoto et al. Optometry and Vision Science, Vol. 78, No. 10, October 2001

Accummodation in Uncorected Ametropia-Tsukamolo el al.76? the overapping groups and the nonuverlapping groups are dasi-om left)appear doe to them.In contras to the oerapping fiad in the different cagurics in terms of the changs of anisome- guups80%of the nonoverapping gnxps of the outside and tropia with accommxlation.Furthermeer.the outside suhjret intersect sbjerts showrd an increase in the derree of aniometto- and the iner subjects in the overlpping group may be dasi- pia as sbown in Fig.4 top right and middk right.This trend was fiod in onc catcgory (p=0.124.x"tor),and thoo:(outside and recugnized cven in the inside suhjocts (Fig,4 boctoen) interseet subjeets)in the nonoverlapping gup my he dassified in The overlapping gromp shjeets ovionsly have more advantage another category (p=0.594,xcest).However,the insidesubjects in binccular function when focusing at far disrances (at the 5-m in the overlapping group and in the nooverapping goup were targes in this paper)than the nonverlapping group subjects.In statisically different (p 0.001.X'tesr).and in relation to the sad.the majurity of the nomowverapping group subjects outside and intersect subpecs cach of them were statistically dif apparently achieved decreasing anisometropi (appeoaching ferent (p0001.x test for both the overlapping and nocover isomeropi)wich accommodation.Even in he approximately appins groups). two-thirds of the inside subjects of the nooverapping group,the c十ot0 ocus on the n7 r target caused a docreasc in anisom心 DISCUSSION tropia(appeoch to isometropia).The change of anisometropia wich accommodation may contribate to the development and The degroe of astigti changod with acommodarion maintenance of binocular vision Referring to anicomcropic as shnwn in Fig.5.The results of the mnst typical sbjeets in terms amhlpi,in the caex that have alme the xime aniomrtnpi of accommodative stimulation are the outside suhjects shown at during the first 2 to 3 years of life,despite the sme trearments. the top of the Fg 5,in all of whom all netinal conjugate points some of them contract amblyopia and sume do not.In the dini, befire acommedition were far away from the point correpond we nftrn examine rwo patients who show different binoculir fiune- ing to accommodative stimulatic (0.5 m in this paper)Roughly tice despite having almest the same other ophthalmic functions. rwo-thirds of them had a change of astigmarism resulting,from a This might result from the difference of the degree of anisomero stronger accommodative response in the vertical meridian than tbe pia with accommodacion. harcantal meridian.This brought an increce in with-the-rul As to the cause of the cnge of anisometrop with accoenmo- astigmatism or a decrease in against-the-rule astia marism.Roughly daion,rintoour previous inveiionsthen one third of sbjects had achange of astigmatism resuking froma of both eyes on accommodation is markedly gested.Further stronger accommodative response in the horicontal meridian than clarification of the mechanisms of accommodtion requires addi- in the vertical mcridian.I'his bruught an incrcase of aginst-tho- ticel imigition,-We should cunsider accommocation rul astigmatism or a decrease of with the rule astigmatism.Of from the point of view of murual interaction of both eyes course,the data plored near the 45 line are no definite,perbaps bccao of tochnical errnrs in miaraan-ment or chue to a fluctsition of accommocarive repom.However,i seems obvious that sg ACKNOWLEDGMENTS matism changes occurred with accommodation in consequence of We aaxe Dr.D.L Cimpow ai ae Witorer Oplthurlocolegiral fuutinte Gr iis different refractive changes in different neridians,and many sub g6gvwd今ean叹Twi灯 ects showed greter refractive changes in the vertical meridian. Nereived September 26 1999:reebhow rereleed Aprl 27.2001. These trends ofastigmatism chnge with accommodation of tbe ouside subjectseed in the intersect subjects and in REFERENCES the inside subjectsIn the inside subjects.in some cases,it ap pcars from obeerving refraction in only on meridian that the 1.Seishin M.Uozato H,Yamamoto K.Makino H.Natao S.Refrecrion soed"ative acommodation"ocurre Oa this point, bchahint in ardinary vicon.Part I:cnnceming aommodarinn bg more invesigation is necessary.During observation ofthe subjects' Foci Ophthalmol Jpn 19821351052-7 2.Sighin M,Uroaro H,Makino H,Nakan S,Yamamom K.Relatinn- pupils,many of them slightly changed thcir size and position on acpomodation.4.It is well lkenown that the oprical yrm of the ship betueen accommodation bg and oculor meridians.J Japan Oph talmol Op.io19g3:4☒7-9. human eyehall isaonsemchrecognixed by the 3.Saishin M.Uoeato H.Malino H.Nakao S.Yamamono K.Lg of esisno of plurall optical visa axis.linc of sghe,pupillary accommudeion.In:Breiain GM.Sid [M.eth.Alvanes in g ais and fiscntion axis.This indicates that in the nononil op- nostic Vhual Opiis:Proceeding ef the Secuad Inlereaconal Sym tical system,the change in sie and position of the pupil resules in posim,Turwon,Arianr,Octuher 23-25,1982.Berlin:Sprinper- a change ofan aperure stop in the optical system.The fic:that the YeI838-4. human lens basadin of refractive indexmy contrbute 4.Saichin M,Ueoaro H,Makino H,Nakan S,Yamamoto K.Dynamir to the dioptric change even when theaperure sopslightly changes reftction in nanral visi orentaion of objecrs.Japn Ophthal ts location in the optical system. m0ris184:563-6 The charges in degree of anisometropea with accommodation 5.Hirai H.Uemura S.Uoearo H.Saishin M.Yamamoto K Color are shown in Fig.4.Contrary to the change of astigmatism,there is ans出2 da:ommmu.iei出iiu.|Ee19863:723-5 6.Hirai H.Nawe Y.Sabhin M.Yaesmoto K A soudy of the relarion a diffonmno betwon the owarlapping groups and the monoverhp- ship the dominant eye and conventiunal munccular viual acity and ping groups.In the oveapping groups the change in the degree of mouucuar vision wtder binocubar coudiliono.Furis Opathalmol Iou anisometropia in terms of increasing or decreasing were almos 1987-38:42-6 50:50 in the outside sbjoxs (Fig,4 top kf)and in the intrs Sishin M.Opcical charxceristies of the buman e J Ophthal- subjeets (Fig.4 middle lefr).Even the inside sbjes (Fig.4 bot- mc5e19948:1m1-12 (lyrewng aud Vafo Sinare Vol,78,No 10.Codhe 2001

the overlapping groups and the nonoverlapping groups are classi￾fied in the different categories in terms of the change of anisome￾tropia with accommodation. Furthermore, the outside subjects and the intersect subjects in the overlapping group may be classi￾fied in one category (p
0.124, 2 test), and those (outside and intersect subjects) in the nonoverlapping group may be classified in another category (p
0.594, 2 test). However, the inside subjects in the overlapping group and in the nonoverlapping group were statistically different (p  0.001, 2 test), and in relation to the outside and intersect subjects, each of them were statistically dif￾ferent (p  0.001, 2 test for both the overlapping and nonover￾lapping groups). DISCUSSION The degree of astigmatism changed with accommodation15–21 as shown in Fig. 5. The results of the most typical subjects in terms of accommodative stimulation are the outside subjects shown at the top of the Fig. 5, in all of whom all retinal conjugate points before accommodation were far away from the point correspond￾ing to accommodative stimulation (0.5 m in this paper). Roughly two-thirds of them had a change of astigmatism resulting from a stronger accommodative response in the vertical meridian than the horizontal meridian. This brought an increase in with-the-rule astigmatism or a decrease in against-the-rule astigmatism. Roughly one-third of subjects had a change of astigmatism resulting from a stronger accommodative response in the horizontal meridian than in the vertical meridian. This brought an increase of against-the￾rule astigmatism or a decrease of with-the-rule astigmatism. Of course, the data plotted near the 45° line are not definite, perhaps because of technical errors in measurement or due to a fluctuation of accommodative response. However, it seems obvious that astig￾matism changes occurred with accommodation in consequence of different refractive changes in different meridians, and many sub￾jects showed greater refractive changes in the vertical meridian. These trends of astigmatism change with accommodation of the outside subjects are also recognized in the intersect subjects and in the inside subjects.22 In the inside subjects, in some cases, it ap￾pears from observing refraction in only one meridian that the so-called “negative accommodation”23 occurred. On this point, more investigation is necessary. During observation of the subjects’ pupils, many of them slightly changed their size and position on accomodation.24, 25 It is well known that the optical system of the human eyeball is a noncoaxial system26, 27 that is recognized by the existence of plural optical axes: visual axis, line of sight, pupillary axis, and fixation axis.28 This indicates that in the noncoaxial op￾tical system, the change in size and position of the pupil results in a change of an aperture stop in the optical system. The fact that the human lens has a gradient of refractive index29–31 may contribute to the dioptric change even when the aperture stop slightly changes its location in the optical system. The changes in degree of anisometropia with accommodation are shown in Fig. 4. Contrary to the change of astigmatism, there is a difference between the overlapping groups and the nonoverlap￾ping groups. In the overlapping groups, the change in the degree of anisometropia in terms of increasing or decreasing were almost 50:50 in the outside subjects (Fig. 4 top left) and in the intersect subjects (Fig. 4 middle left). Even the inside subjects (Fig. 4 bot￾tom left) appear close to them. In contrast to the overlapping groups, 80% of the nonoverlapping groups of the outside and intersect subjects showed an increase in the degree of anisometro￾pia as shown in Fig. 4 top right and middle right. This trend was recognized even in the inside subjects (Fig. 4 bottom). The overlapping group subjects obviously have more advantage in binocular function when focusing at far distances (at the 5-m target in this paper) than the nonoverlapping group subjects. In￾stead, the majority of the nonoverlapping group subjects apparently achieved decreasing anisometropia (approaching isometropia) with accommodation. Even in the approximately two-thirds of the inside subjects of the nonoverlapping group, the effort to focus on the nearer target caused a decrease in anisome￾tropia (an approach to isometropia). The change of anisometropia with accommodation may contribute to the development and maintenance of binocular vision.32–34 Referring to anisometropic amblyopia, in the cases that have almost the same anisometropia during the first 2 to 3 years of life, despite the same treatments, some of them contract amblyopia and some do not. In the clinic, we often examine two patients who show different binocular func￾tion despite having almost the same other ophthalmic functions. This might result from the difference of the degree of anisometro￾pia with accommodation. As to the cause of the change of anisometropia with accommo￾dation, referring to our previous investigations,1–7 the interaction of both eyes on accommodation is markedly suggested. Further clarification of the mechanisms of accommodation requires addi￾tional investigation.35–55 We should consider accommodation from the point of view of mutual interaction of both eyes. ACKNOWLEDGMENTS We thank Dr. D. L. Guyton of the Wilmer Ophthalmological Institute for his insightful comments and help in using terminology. Received September 28,1999; revision received April 27, 2001. REFERENCES 1. Saishin M, Uozato H, Yamamoto K, Makino H, Nakao S. Refraction behabior in ordinary vision. Part 1: concerning acommodation lag. Foria Ophthalmol Jpn 1982;33:1052–7. 2. Saishin M, Uozato H, Makino H, Nakao S, Yamamoto K. Relation￾ship between accommodation lag and ocular meridians. J Japan Oph￾thalmol Optics 1983;4:87–9. 3. Saishin M, Uozato H, Makino H, Nakao S, Yamamoto K. Lag of accommodation. In: Breinin GM, Siegel IM, eds. Advances in Diag￾nostic Visual Optics: Proceedings of the Second International Sym￾posium, Tucson, Arizona, October 23–25, 1982. 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