Influence Of Lens Position Detected By An Anterior Segment Analysis System On The Prognosis Of Cataract Surgery

Purpose:To predict postoperative intraocular lens(IOL)position using the Sirius Anterior Segment Analysis System and investigate the effect of IOL position and IOL type on postoperative refraction,in order to reduce the IOL calculation error.Methods:In total,97 patients(102 eyes)were enrolled in the final analysis.An anterior segment biometry measurement was performed preoperatively with Sirius Anterior Segment Analysis and Lenstar LS900.The results of predicted lens position(PLP)was automatically calculated by a software of the instruments.The surgical phacoemulsification with an IOL implantation in the capsular bag after a circular capsulorhexis was performed in all cases.Effective lens position(ELP)was measured manually 3 months postoperatively.Postoperative spherical refraction determined by subjective refraction was used in subsequent calculations.Pearson’s correlation analysis and linear regression analysis were used to determine the correlation of lens position to other parameters(axial length,aqueous depth,lens thickness,white to white,mean corneal curvature).Results:PLP and ELP were positively correlated to axial length(AL)(r=0.42,P<0.0001 and r=0.49,P<0.0001),respectively.No linear correlation was observed between AL and the prediction error of lens position(peLP)(r=0.17,p=0.09).There is a weak linear correlation between lens thickness(LT)and PLP(r=-0.20,P=0.04),and there is no linear correlation between LT and ELP(r=0.06,P=0.57).There was a moderate linear correlation between aqueous depth(AD)and PLP or ELP(r=0.63,P<0.0001;r=0.47,P<0.0001).There was a negative linear correlation between AD and LT(r=-0.55,P<0.0001).ELP was found to have the strongest correlation with a new variable(AD+0.6 LT)through multiple regression(r=0.61,P<0.0001).There is no significant linear correlation between IOL position and white to white(WTW)or mean corneal curvature(Avg K).There was a weak correlation between the peLP and the prediction error of spherical refraction(peSR)(r=0.34,P<0.0001).There are statistical differences in the position of three types IOL.The peLP of Softec HD statistically differed from that of TECNIS ZCB00 and of Sensor AR40E,respectively.Conclusion:The Sirius Anterior Segment Analysis System could reasonably predict ELP,which reduced the IOL power formula prediction error.ELP had an effect on postoperative refraction.IOL movement away from the retina produced myopia,while movement close to the retina produced hyperopia.The longer the AL,the more obvious the tendency is for IOL to drift toward hyperopia.The softer the loops of IOL,the worse the stability of IOL within capsular bags.