Purpose: To estimate the cumulative probability of Nd:YAG laser posterior capsulotomy after cataract extraction in a geographically defined population.
Methods: Rochester Epidemiology Project databases were used to identify retrospectively all Nd:YAG laser posterior capsulotomies performed on Olmsted County, Minnesota, residents who had previously undergone cataract extraction between 1988 and 1996, inclusive. Demographic data and potential risk factors for laser, including age, sex, surgical technique, year of surgery, and intraocular lens material, were obtained by chart review or by retrieval from computer databases. The cumulative probability of Nd:YAG laser posterior capsulotomy was calculated by Kaplan-Meier estimates, and risk factors were analyzed using the Cox proportional hazards model.
Results: A total of 925 Nd:YAG laser posterior capsulotomies were identified after 3541 cataract extractions in 2718 patients. The cumulative probability of Nd:YAG laser posterior capsulotomy after cataract surgery was 6% (95% confidence interval = 5% to 7%) at 1 year, increasing to 38% (35% to 40%) at 9 years. Young age at the time of surgery (P =.02), polymethylmethacrylate intraocular lens material (P <.001), earlier year of surgery (P <.001), and extracapsular extraction (in comparison with phacoemulsification, P <.001) were found to increase significantly the risk of subsequent Nd:YAG laser posterior capsulotomy. Women tended to have a greater probability of Nd:YAG laser posterior capsulotomy (P =.17), but this difference was not statistically significant.
Conclusions: Nd:YAG laser posterior capsulotomy was common after cataract surgery but infrequent during the first postoperative year. Prolonged follow-up is necessary in investigations of the effects of new cataract surgery technologies on the probability of capsulotomy.