Purpose: To model the effect of the introduction of square-edged intraocular lenses (IOLs) in the United States on neodymium:YAG (Nd:YAG) laser capsulotomy rates and to compare the model with actual capsulotomy rates.
Setting: Ophthalmology Department, St. Thomas' Hospital, London, United Kingdom, and Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.
Methods: The actual numbers of cataract surgeries and Nd:YAG laser capsulotomies performed in the U.S. were obtained from Medicare claims data for 1993 to 2003. The percentage market share of square-edged IOLs was obtained, and numbers of square-edged and round-edged IOLs implanted were calculated. Predicted laser capsulotomy rates were modeled on published postmortem and clinical data and compared with actual capsulotomy rates.
Results: Between 1993 and 2003, the number of cataract surgeries and Nd:YAG laser capsulotomies reimbursed by Medicare rose by 67.4% and 18.9%, respectively. After the introduction of square-edged IOLs in 1995, the market share grew to 48.5% in 2003. The total number of Nd:YAG capsulotomies reimbursed by Medicare in 2003 exceeded the number of capsulotomies predicted by the model by at least 23.9%. The estimated cost generated by the discrepancy between predicted and actual laser capsulotomies in 2003 was at least US $30 million.
Conclusions: After the introduction of square-edged IOLs, Nd:YAG laser capsulotomy rates decreased, but not by as much as predicted. The additional cost to the Medicare system was more than US $30 million higher than the model predicted.