Clinical Analysis Of Posterior Intraocular Lens Dislocation

Objective To identify the predisposing factors and clinical characteristics of posterior chamber intraocular lens(PC-IOL)dislocation,and to compare the surgical outcomes following treatment of dislocated intraocular lens.Methods This study is a retrospective analysis of all cases of posterior intraocular lens dislocation from September 2007 until September 2017 and presented to the Yuhuangding Hospital,73 eyes of 70 patients were enrolled.All cases were divided into early intraocular lens dislocation group(<3 months)and late intraocular lens dislocation group(?3 months)according to the time of occurrence.The evaluated medical records including primary disease and surgery,previous surgical history,ocular complication,axial,causes and risk factors of dislocation,interval between cataract surgery and dislocation,type and degree of dislocation of intraocular lens,type of the dislocated intraocular lens,surgical methods in dislocation,preoperative and postoperative best corrected visual acuity(BCVA),postoperative complications and postoperative stability.The statistical analyses were performed with the SPSS ver.20 software.Preoperative and postoperative BCVA were compared by T test.The efficacy in achieving postoperative BCVA of IOL repositioning and IOL exchange were compared by repeated measures Anova.The significance of diff erences in the incidence of postoperative complications was tested by chi-square test,and P<0.05 as a significance difference standard.Results There are 11 eyes in early IOL dislocation group,the mean interval between cataract surgery and dislocation are 1.08±1.05 months and the shortest interval is one day.There are 62 eyes in late IOL dislocation group,the mean interval between cataract surgery and dislocation are 93.6±62.3 months and the longest interval is twenty-one years.In this study,early IOL dislocation mostly associated with surgical complications such as capsular rupture and inadequate fixation of IOL,including 9 eyes(81.8%)with posterior capsular rupture,1 eye(9.1%)with history of trauma.Late IOL dislocation mostly associated with zonular weakness and capsular bag contraction,including 12 eyes(19.4%)with history of trauma,27 eyes(43.5%)with zonular dehiscence and 16 eyes(25.8%)with posterior capsular rupture.In addition,there are several predisposing factors may increase the incidence of IOL dislocation,including high myopia(30.1%),prior vitrectomy(20.5%),uveitis(10.9%),retinitis pigmentosa(6.8%)and pseudoexfoliation syndrome(5.5%).In our study,there are 11 eyes of early out-of-bag IOL dislocation,30 eyes(48.4%)of late in-the-bag IOL dislocation and 32 eyes(51.6%)of late out-of-bag IOL dislocation.There are 71 eyes underwent surgery,including IOL reposition in 29 eyes(39.7%),IOL exchanging in 8 eyes(10.9%),pars plana vitrectomy combined with IOL reposition in 4 eyes(19.2%)and pars plana vitrectomy combined with IOL exchanging in 17 eyes(23.3%).There are significant difference in BCVA between preoperative and postoperative(t=-5.77,P<0.001).There are no significant difference in BCVA between reposition and exchange(P=0.24).Conclusion PC-IOL dislocation is one of the rare complications after cataract surgery.The mainly causes of IOL dislocation are capsular rupture and zonular dehiscence.High myopia,prior vitrectomy,capsular contraction synd rome,retinitis pigmentosa and uveitis are predisposing factors for IOL dislocation.Considering the complexity of intraocular lens dislocation,it is necessary to choose the proper surgical methods according to specific conditions.Preoperative system evaluation and strict follow-up after surgery can prevent the occurrence of IOL dislocation and reasonable management can improve the BCVA effectively.