| Objective:To investigate the prevalence of aniseikonia among myopic patients in ophthalmologyof the Affiliated Hospital of North Sichuan Medical College,and analyze the relationship of aniseikonia with the difference of diopter and axial length.To explore the factors that may cause aniseikonia.Methods:A cross-sectional study.Myopia patients(4～40 years)who underwent optometry in the ophthalmology of the Affiliated Hospital of North Sichuan Medical College were collected.ARK-510A autorefractor,Dk-700 optometry system were used for optometry.IOL-Master 700 was used for the measurement of axial length.Aniseikonia were evaluated by the binocular aniseikonia test charts.Gender,age,diopter(spherical degree,cylindrical degree,spherical equivalent),axial length and aniseikonia were recorded.Spearman test,chi-square test and multiple linear regression were used to analyze the aniseikonia with the differences of diopter and axial length.At the same time,ROC curves of the difference of diopter and axial length were drawn for aniseikonia.Results:A total of 322 patients(159 males and 163 females)were included,with an average age of(17.77±7.69)years,the overall prevalence rate of aniseikonia were 15.22%(49 cases).In univariate analysis,the absolute values of all parameter were included in the analysis.The differences of spherical degree(r=0.449,P<0.001),cylindrical degree(r=0.596,P<0.001),spherical equivalent(r=0.479,P<0.001)and axial length(r=0.417,P<0.001)were all positively correlated with aniseikonia.Multivariate analysis is shown that the difference between the cylindrical degree and the sphericalequivalent has a greater influence on aniseikonia.The regression equation is Y=0.009-0.626X1(cylindrical degreedifference)-0.22 X2(sphericalequivalent difference)(F=159.17,P<0.001,adjusted R2=0.496).In the analysis of risk factors,it is found that when the difference of spherical degree is more than-2.00 D,and the cylindrical degree and spherical equivalentis more than-1.00 D,the risk of aniseikonia can be increased.In the diagnostic analysis,it was found that the difference of cylindrical degreehad the highest value(AUC=0.778;95%CI:0.69～0.87;P<0.0001;sensitivity=53.06%,specificity=99.63%).Conclusion:The prevalence of aniseikonia in myopia patients is high,which should be paid great attention to in clinical diagnosis and treatment.Anisometropia does not necessarily lead to aniseikonia,but the difference between cylindrical degree and spherical equivalent is the key factor leading to aniseikonia.Objective:The effect of aniseikonia on binocular function were studied based on different magnification of afocal magnifies.Methods: Aprospective self-controlled study.A total of 53 undergraduate and graduate students(24 males and 29 females)from North Sichuan Medical College were collected to measure their binocular visiual acuity,binocular function(stereoacuity,fusionalvergence and accommodation)and visual fatigue under the four degree of aniseikonia: 0%,3%(place a 3% afocal magnifies in the right eye),5%(place a 5% afocal magnifies in the right eye)and 8%(place a 8% afocal magnifies in the right eye).At the same time,according to gender and myopia group,the differences of stereoacuity were compared.Using nonparametric test for statistical analysis.After multi-group analysis,pairwise comparison was made and the adjusted P value was recorded.The difference was statistically significant if the P value was less than 0.05.Results: There were statistically significant differences in binocular visual acuity and binocular function under the four degree of aniseikonia (0%,3%,5% and 8%)(P<0.001).In pairwise comparison,it was found that3% degree of aniseikonia could lead to the decrease of accommodation amplitude(P=0.0128)and the break point in near positive fusional vergence(P<0.001);5% degree of aniseikonia can cause the binocular visiual acuity,stereoacuity,distant fusional vergence(the break and recovery point of negative fusional vergence;the blur,break and recovery point of positive fusional vergence),near fusional vergence(the blur,break and recovery point of negativefusional vergence;the break and recovery point of positive fusional vergence);near point of convergence(the break and recovery point);accommodative responce and accommodative facility to decrease obviously,the difference was statistically significant(P<0.001).8% aniseikonia can lead to severe visual fatigue(P<0.001).Conclusion: The size of aniseikonia can significantly affect binocular function.3% degree of aniseikonia may reduce the accommodative amplitude and the near positive fusionalvergence,while 5% degree of aniseikonia can reduce the binocular visiual acuity and binocular function.8%aniseikonia can lead to severe visual fatigue.We should pay great attention to aniseikonia in clinical diagnosis and treatment to avoid further visual dysfunctiQn. |
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