To use the techniques of survival analysis to analyze the incidence of anterior subcapsular opacities (symptomatic and asymptomatic) and clinically significant cataract in the US Food and Drug Administration clinical trial of the Visian Implantable Collamer Lens (ICL).METHODS
Five hundred twenty-six eyes were followed for an average of 4.7 years; 89% (468 eyes), 73% (384 eyes), and 59% (311 eyes) were seen at 3, 4, and 5 years or later, respectively. Anterior subcapsular opacities were defined as trace or more (≥0.6 LOCS III opacity). Clinically significant cataract required loss of 2 or more lines of best spectacle-corrected visual acuity (BSCVA), a significant increase in glare symptoms, or cataract extraction. Kaplan-Meier analyses of opacities and cataract were performed.RESULTS
The Kaplan-Meier cumulative probability estimate for anterior subcapsular opacities over 7+ years of follow-up was 7% whereas 31 (5.9%) eyes were actually observed. Anterior subcapsular opacities generally occurred early with 58% seen in the first year, 68% in the first 2 years, and 74% in the first 3 years. The cumulative probability estimate for clinically significant cataracts over the 7+ years of follow-up was 2% whereas 7 (1.3%) were actually observed. The difference between the Kaplan-Meier estimate and the actual observed percentage is due to the fact that the former takes into account the differences in postoperative follow-up time of individual eyes. Preoperative myopia (>12.00 diopters) and patient age (>40 years) were significant factors in the development of cataract. No loss of BSCVA was observed in any eye following cataract extraction.CONCLUSIONS
Approximately 6% to 7% of eyes develop anterior subcapsular opacities at 7+ years following ICL implantation but only 1% to 2% progress to clinically significant cataract during the same period, especially very high myopes and older patients. Visual outcome following cataract extraction was good.