Posterior capsule opacification following extracapsular cataract extraction is a manifestation of proliferation of anterior lens epithelium onto the posterior capsule. In addition to Elschnig pearl formation, vision is decreased in two ways. Multiple layers of proliferated epithelium produce a frank opacity. Also, the lens cells show myofibroblastic differentiation and their contraction produces numerous tiny wrinkles in the posterior capsule resulting in visual distortion. Because the cells that proliferate are anterior lens epithelial cells and because proliferation begins at the site of apposition of anterior capsular flap and the posterior capsule, a wide anterior capsulectomy should help reduce the risk of and delay the onset of visual loss from this complication of extracapsular surgery. Polishing the posterior capsule at the time of surgery will not help in this regard unless there is a complicated cataract with pre-existing posterior migration of lens epithelium. The presence of a potential cleavage plane between the proliferating epithelium and the posterior capsule provides a therapeutic alternative to surgical or laser discission.