Surface scattering in implanted hydrophobic intraocular lenses

PURPOSE: To describe surface scattering, a new phenomenon in polyacrylic intraocular lenses (IOLs), and discuss the possible cause of this finding. SETTING: Showa University, Fujigaoka Hospital, Yokohama, Kanagawa, Japan. METHODS: This observational case series involved 40 patients who received the AcrySof(R) IOL (Alcon Laboratories, Inc.) as part of a clinical trial in 1991. Four patients (5 eyes) were evaluated. Thirty-three patients had the same surgery in 1999, and the findings in these patients were compared with those in the earlier patients. Lens surface scattering was evaluated by area densitometry using Scheimpflug photography. No statistical analysis was done because of the small sample size. RESULTS: The 5 IOLs implanted in 1991 showed various degrees of surface scattering. The degree of scattering was greater than that in the 1999 group. There was no degradation in visual performance and no manifestation of intraocular inflammation or other adverse effect from the IOLs in either group. Attempts to remove foreign material on the IOL using the neodymium:YAG (Nd:YAG) laser were unsuccessful. CONCLUSIONS: The surface scattering did not appear to be due to deposition of foreign material on the IOL surface. Densitometry and the results of Nd:YAG laser treatment suggest that the changes occurred in the near-surface layer. Phase separation of water near the IOL surface in the inherently hydrophobic material may explain the phenomenon. Newer AcrySof IOLs appear to have less surface scattering.