Pathogenesis of capsular opacification after extracapsular cataract extraction. An animal model.

Opacification of the posterior capsule is the most common post-operative complication of extracapsular cataract surgery. We studied the sequential changes in the posterior capsule of the aphakic cat and monkey after extracapsular surgery using light microscopy, scanning electron microscopy, and transmission electron microscopy. In the cat, but not the monkey, there was proliferation of a pigment-containing membrane arising from the iris root and ciliary body, and extending onto the residual lens capsule. In both animals there was transformation of residual lens epithelial cells to fibroblasts which contain contractile elements (myofibroblasts) and are associated with collagen deposition. In the cat, pigment epithelial cells from the iris or ciliary body, as well as the transformed lens epithelial cells, contributed to late opacification of the posterior capsule.