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Cataract surgery is routinely performed to replace the clouded lens by a rigid polymeric intra-ocular lens unable to accommodate. By implanting a silicone gel into an intact capsular bag the accommodating properties of the natural lens can be maintained or enhanced. The implantation success of accommodating lenses is hampered by the occurrence of capsular opacification (PCO) due to lens epithelial cell (LEC) growth. In order to prevent LEC proliferation, a treatment regime using actinomycin D, cycloheximide and water was developed. The effectiveness of treatment was analyzed using an in vitro, MTT-based cell culture system and an ex vivo pig eye model in which the implanted lens-in-the-bag is cultured as a whole. LEC were exposed to treatment solutions for 5 min, then the cells were allowed to recover and to re-colonize the substratum. MTT conversion by cells was transiently inhibited by cycloheximide dissolved in water and by water alone. Exposure to actinomycin D resulted in a lasting inhibition of MTT conversion and consequently cell proliferation. These in vitro data could not be fully reproduced in the ex vivo pig eye model due to essential differences between both models. Treatment with actinomycin D containing solutions, however, resulted in a nearly complete absence of cells on the capsular wall. The pig eye model is a promising approach to further evaluate the effects of peri-surgical treatment during the accommodating intra-ocular lens implantation.

The aim of this study is to determine rigid gas permeable (RGP) lens surface properties prior to and after wear that are influential on adhesion of Pseudomonas aeruginosa. After 10 and 50 days of wear and after end-stage use, lenses were collected for determination of physico-chemical surface properties and bacterial adhesion in a parallel plate flow chamber. Water contact angles on unused RGP lenses amounted 47+/-13 degrees and were affected by wear. In addition, %O at the lens surfaces, as determined by X-ray photoelectron spectroscopy increased after use for 10 and 50 days, but decreased after end-stage wear. The %N hardly increased after wear and, in line, SDS-PAGE did not indicate adsorbed proteins. The surface roughness of the lenses, as measured by atomic force microscopy amounted 9 nm after 10 and 50 days of use, but end-stage lenses were significantly rougher (48+/-23 nm). Moreover, initial deposition of P. aeruginosa #3 increased with increasing roughness for end-stage lenses. Multiple regression analysis, however, revealed that both physical and chemical surface properties were predictive for initial bacterial deposition to lens surfaces. After 10 days of wear, bacterial deposition was governed by the water contact angle, surface roughness, %O, %N, and %Si, while after 50 days of wear the surface roughness, %N, and %Si were found predictive for bacterial deposition. Initial bacterial deposition to end-stage lenses was solely dependent on the surface roughness. Summarizing, physico-chemical surface properties of RGP lenses change slightly during the first 10-50 days of wear, but end-stage lenses all had increased surface roughness, concurrent with increased bacterial adhesion.