Evaluation of corneal endothelium before and after neodymium : Yttrium-aluminium-garnet laser capsulotomy in posterior capsular opacification

Abstract

Aim: The aim of this study is to evaluate the corneal endothelial changes before and after neodymium:yttrium-aluminium-garnet (Nd:YAG) laser posterior capsulotomy in patients with posterior capsular opacification (PCO) among adults. Materials and Methods: This prospective non-comparative study was carried out in 200 eyes of 200 adult patients with clinically diagnosed PCO. Eyes were later subjected to Nd:YAG laser capsulotomy and followed up at 1-12 weeks to evaluate the damage caused by laser on the corneal endothelium. Computerized morphometry was used to evaluate the central corneal thickness, size, shape and cellular density, coefficient of variation and hexagonality of the endothelial cells using non-contact specular microscopy before and after laser capsulotomy. Data was analyzed using Chi-square and t-test and P < 0.05 were considered significant. Results: Endothelial cell density (ECD) varied from 1659 to 2792 cells/mm 2 with a mean of 2298.7 cells/mm 2 before laser treatment. At 1 week, the mean ECD was 2178.1 cells/mm 2 (P < 0.0001) and 12 weeks was 2121.3 cells/mm 2 (P < 0.0001). The difference between pre-laser ECD and ECD at 1-12 week was 120.6 cells/mm 2 and 177.4 cells/mm 2 (7.78%) respectively which was found to be highly significant. Hexagonality of corneal cells varied from 49% to 84% with a mean of 72.22% pre-laser. At 1 week, hexagonality was 71.42% (P < 0.005) and at 12 weeks was 70.22% (P < 0.0001). The difference was clinically significant. 90% patients had two or more than two Snellen's line visual improvement. Conclusion: In our study, although there was a dramatic improvement in visual acuity after laser capsulotomy, we found a significant reduction of ECD. Although Nd:YAG laser capsulotomy presents the advantage of being non-invasive and effective method to treat PCO, the corneal endothelium may be damaged by laser radiation.