Difference analysis of Orbscan Ⅱz corneal topography in anisometropic amblyopes:a contralateral eye study / 中华实验眼科杂志

ABSTRACT

Background The characteristics of anisometropic amblyopia in ocular morphology are becoming a hot topic in amblyopia field.And the interocular difference in corneal parameters of anisometropic amblyopia is to be understood here.Corneal topography is a non-invasive method for in vivo corneal examination and applied in our study.Objective This study was to investigate the interocular difference of corneal topography in anisometropic amblyopic patients Methods This was a serial cases observation.Thirty anisometropic amblyopes were selected in Center for Optometry and Visual Science,People's Hospital of Guangxi Zhuang Autonomous Region.The patients were divided into amblyopic eye group and fellow eye group based on the best corrected distance visual acuity.Corneal topography was examined with Orbscan Ⅱ z,and corneal morphological parameters such as Diff values of the anterior and posterior corneal surface,Sim K 's astigmatism,Kmax,angle kappa and central corneal thickness (CCT) were measured.The interocular differences in these parameters were evaluated by paired t test,and the correlations in these parameters between the amblyopic eyes and the fellow eyes were analyzed by Pearson linear correlation and simple regression analysis.Results The Diff values of the anterior corneal surface were (0.011±0.006)mm and (0.011±0.017)mm,and those in the posterior corneal surface were (0.031 ±0.012)mm and (0.026 ±0.008)mm in the amblyopic eye group and the fellow eye group,respectively.In addition,Sim K's astigmatism were (1.8± 1.1)D and (1.1 ±0.6) D,JCC were (77±80) °and (100±80) °,J0 values were (-0.17±0.72) D and (0.02±0.41) D,J45 values were (-0.16±0.79) D and (0.13 ±0.48) D,CCT values were (551 ±37) μm and (551 ±31) μm,angle kappa values were (6.4± 1.4) ° and (4.9 ± 1.2) ° in the amblyopic eye group and the fellow eye group,respectively.Significant differences were found in the Diff values of the anterior and posterior corneal surface,Sim K's astigmatism and angle kappa between the two groups (t=-3.041,P=0.005 ;t=-4.317,P=0.000 ;t=-4.571,P=0.000).Pearson's linear correlation test demonstrated significant interocular positive correlations in parameters such as the anterior corneal surface Diff values (r =0.444),J0 (r =0.383),posterior Diff values (r =0.600),and Sim K 's astigmatism (r =0.479),and CCT (r =0.948,P＜0.05).The linear regression equation between the two groups was Y =-0.005 +1.392X (R2 =0.197,F=6.858,P=0.014) in the Diff values in the anterior corneal surface,Y =-0.013+0.421X (R2=0.360,F=15.761,P=0.000) in the Diff values in the posterior corneal surface,Y =0.616+0.27X (R2=0.230,F=8.348,P=0.007) in the Sim K's astigmatism,Y=0.060+0.219X (R2 =0.147,F=4.814,P=0.037) in theJo and Y=i08.289+0.804X (R2 =0.899,F=250.293,P=0.000) in CCT.Conclusions Corneal morphological interocular differences exist significantly in anisometropic amblyopic patients.