Abstract
Abstract: :
Purpose:Cataract formation after phakic intraocular lens (PIOL) [anterior chamber (AC)–PIOL, iris–fixated (IF)–PIOL, and posterior chamber (PC)–PIOL] surgery has been a subject of concern. We performed a comprehensive review of published literature to determine the incidence, type and outcomes of new onset and progressive cataracts and to explore predisposing factors and possible mechanisms of cataract formation after PIOL implantation. Methods:A MEDLINE search from 1966 to June 2003 and bibliography retrieval were conducted to identify articles evaluating clinical results and/or complications after PIOL implantation. 90 articles were included in our analysis. Results: Of the total 4,358 eyes in the study, 3.72% were noted to have new onset or preexisting progressive cataracts. Among the preexisting cataracts, 24.4% were documented to be progressive after PIOL surgery. The overall incidence of cataract formation/progression in the AC, IF, and PC–PIOL were 1.36%, 1.16%, and 7.25% respectively. Of the 3 models of AC–PIOLs (ZB, ZB5M, and NuVita lens), cataracts were observed only in the ZB5M implant (2%). In the IF–PIOL group, the incidence was 0.74%, 1.29%, and 0.66% for the Worst–Fechner biconcave lens, myopic Artisan lens, and hyperopic Artisan lens respectively. In the PC–PIOL group, the incidence was 17.52% for the Chiron–Adatomed lens, and 6.58% for the Staar Collamer lens. Among the new onset cataracts, nuclear sclerosis was the predominant type in the AC (100%), cortical vacuole in the IF (61.5%), and anterior subcapsular cataract (ASC) (88.5%) in the PC group. Most ASCs were noted to be nonprogressive or slowly progressive. All of the new onset nuclear sclerotic cataracts required surgery. In most AC and IF–PIOLs, cataract formation was idiopathic. In the PC–PIOL group, early cataract formation tends to be related to surgical trauma and late onset cataracts related to IOL–crystalline lens contact. The most common reason for PIOL explantation in the AC and PC lens groups was cataract formation, and in the IF lens group it was corneal endothelial cell loss. Conclusions: The results from published literature suggest that cataract formation is most likely to occur following PC–PIOL in comparison to AC and IF–PIOL implantation. Patients with preexisting progressive cataracts should be informed about the possibility of cataract progression after PIOL implantation. Surgical intervention results in restoration of visual acuity.
Keywords: cataract • refractive surgery: phakic IOL