Relationship between accommodation and lens vault following implantable contact lens surgery / 中华实验眼科杂志

ABSTRACT

Background Implantable contact lens (ICL) surgery is a primary intraocular refractive corrective surgery for high myopia.However,whether there will be enough distance between ICL and anterior face of lens to avoid the occurrence of anterior capsular cataract in non-accommodated and the largest physiological accommodated state after ICL implantation is worthy of investigation.Objective The purpose of this study was to investigate the alteration of lens vault after ICL implantation and explore the relationship between accommodation and change of lens vault.Methods A observational study was carried out.Sixty-six eyes of 33 patients with high myopia who received ICL implantation were enrolled in Affiliated First Hospital of Guiyang Medical College from May to November,2012.Best corrected visual acuity (BCVA),uncorrected visual acuity (UCVA),refractive diopter were regularly examined using synthetical optometry,and crystalline lens rise (CLR) and lens vault in non-accommodative or accommodative condition were observed by the anterior segment OCT (Visante OCT) and ultrasound biomicoscopy (UBM) before operation and 1 day,1 week,l month and 3 months after operation.Data were analyzed with SPSS version 16.0.Repeated measurement one-way analysis of variance was used to compare the differences of vision and refractive diopter among various time points.The relationship between accommodation and CLR was assessed using Pearson linear correlation.The alteration of CLR with accommodation change was analyzed by linear regression equation.Lens vault was measured and compared between non-accommodation and maximal physical accommodation status by paired t test.Results The postoperative UCVA was improved in comparison with preoperative BCVA,and the postoperative diopter was significantly lower than that of preoperation,with significant differences among various time points (F =16.904,P =0.000 ; F =1.498,P =0.000),and the diopter was stable after operation.A positive correlation was found between the alteration of CLR and accommodation under the physical accommodative stimulation in high myopic eyes (R2 =0.49,P =0.00).Under physiological accommodation,CLR elevated 20 μm for per 1.0 D accommodation.In addition,the difference of lens vault values within postoperative 3 months was statistically significant (F=16.025,P=0.000).The lens vault values lowed with the enlargement of accommodation in 48.5％ eyes,and the lens vault values increased with the enlargement of accommodation in 50.0％ eyes.However,1.5％ of the lens vault were in a stable state under the maximal physiological accommodated condition 3 months after operation.Lens vault were greater than zero in 97.0％ eyes (64/66),and only 3.0％ eyes (2/66) were zero under the maximalphysiological accommodated condition.Significant differences were seen in the lens vault between nonaccommodated and the maximal physiological accommodated state 1 day or 1 week after operation (t =4.755,P =0.000 ;t =3.327,P =0.001) ; but there was no statistical significance in 1 month or 3 months after operation (t =1.544,P=0.127,t=0.621,P=0.537).Conclusions During physiological accommodation,the alteration of CLR with accommodation in high myopic eyes.The location of ICL in the eyes is unstable within 3 months after operation.Majority of operative eyes remain enough vault in the maximal physiological accommodated state,but minority of operative eyes occur contact of ICL with the anterior surface of lens.Whether this contact causes anterior capsular cataract still needs to study.