Natural history of cellular deposits on the anterior intraocular lens surface

Previous cytopathological studies have demonstrated the presence of cellular deposits on the poly(methyl methacrylate) (PMMA) intraocular lens (IOL) surface. In this prospective study, IOL surface specular microscopy was used to document the natural history of these deposits in the first year following PMMA IOL implantation. Intraocular lens surface specular microscopy was performed 1, 3, 6, and 12 months after endocapsular cataract surgery in 27 otherwise normal eyes. Postoperatively, IOLs were assessed for the presence of inflammatory cells, with the number of cells graded from 0 (none) to 4 (many). Two inflammatory cell types were visualized: small and giant cells. Small cells were found on 81.5% of IOLs at 1 month, 73.1% at 3 months, and 30.4% at 12 months. Small cells were found in only small numbers (peak mean cell score of 1.26 +/- 0.94 at 1 month). Giant cells were found on 59.3% of lenses at 1 month, 73.1% at 3 months, and 39.1% at 12 months. The number of giant cells on each lens peaked at 3 months (mean cell score 2.0 +/- 1.55), when 50% of lenses achieved a giant cell score of 3 or 4. Inflammatory cell deposits are, therefore, a normal occurrence on the PMMA IOL surface for up to 1 year after surgery. This cellular response consists of two distinct processes: a small cell response, which peaks by 1 month, and a later giant cell response, which peaks at 3 months.