Scanning electron microscopic analysis of foldable acrylic and hydrogel intraocular lenses

To analyze the surface quality of foldable acrylic and hydrogel intraocular lenses (IOLs).

Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, and Institute of Anatomy and Cellular Biology, University of Giessen, Germany.

We studied eight foldable IOL models with optics made of six different acrylate/methacrylate polymers: Acrylens ACR360 (loptex), AcrySof MA60BM (Alcon), MemoryLens U940A (Mentor), 92S and 92C (Morcher), Hydroview H60M (Storz), HydroSof SH30BC (Alcon), and ISH66 (Corneal). Four IOLs of each design were examined. Light and scanning electron microscopy were performed before and after IOL folding with forceps.

All IOL models had excellent optic and haptic surfaces. The haptic-optic junctions revealed minimal empty spaces or irregularities in three of the five three-piece IOLs and smooth surfaces in all one-piece IOLs. Minimal surface alterations and superficial defects caused by folding were detectable in the two acrylate (acrylic) IOLs (loptex ACR360, Alcon MA60BM) with low water content.

Intraocular lenses of acrylate/methacrylate polymers had excellent surface quality. The acrylic IOLs were vulnerable to mild folding or forceps defects; however, these were less marked than those previously noted with poly(methyl methacrylate) IOLs.