Decentration associated with asymmetric capsular shrinkage and intraocular lens design in a rabbit model

We evaluated intraocular lens (IOL) decentration resulting from asymmetric capsular shrinkage. In 19 eyes of 10 white rabbits, a D-shaped incision was made in the anterior capsule and one of three IOL types implanted in the capsular bag: three-piece with polypropylene haptics, one-piece all-poly-(methyl methacrylate) (PMMA), or compressible disk. Eight weeks later, eyes were enucleated for assessment of IOL decentration. Mean decentration was 0.75 mm for three-piece IOLs, 0.46 mm for one-piece IOLs, and 0.30 mm for compressible-disk lenses. Decentration was significantly less in eyes with compressible-disk lenses than in those with three-piece IOLs. Although decentration was less with the compressible-disk lens, the lens is not commonly used because of the large incision and special insertion technique required. If an open-loop IOL is to be used in eyes at risk for asymmetric capsular shrinkage, our results indicate that an all-PMMA one-piece IOL would be preferable to a three-piece lens with a polypropylene haptic.