Security of capsular fixation: small-versus large-hole plate-hepatic lenses

PURPOSE: To assess the effect of relatively large positioning holes on the security of capsular bag fixation of plate-haptic silicone intraocular lenses (IOLs). SETTING: Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: This study tested the hypothesis that larger holes allow ingrowth of lens material, fibrous tissue, or both through them, which helps fixate the lens more firmly in the capsular bag. Five rabbits had bilateral continuous curvilinear capsulorhexis, phacoemulsification, and implantation of a plate-haptic silicone IOL. An IOL with a small, round positioning hole (Staar AA-4203V) was implanted in the right eye in each rabbit, and a large-hole IOL (Staar AA-4203VF) was implanted in the left eye. After 2 months, all rabbits were killed. The force required to extract one haptic from the capsular bag was measured with a digital force meter. All eyes had histopathological analysis. RESULTS: It was slightly more difficult to extract a large-hole IOL from the capsular bag, although this trend was not statistically significant. However, histopathological analysis consistently showed 360 degree synechia formation through the holes, showing that the IOL could be securely fixed in position. CONCLUSIONS: Proliferation of lens epithelial cells through a large positioning hole in a plate-haptic silicone IOL may improve the long-term security of capsular bag fixation. This will help reduce the incidence of IOL decentration and dislocation.