Intraocular lenses: secondary membranes; cystoid macular edema.

In 650 consecutive Binkhorst lens implants, secondary membrane surgery was required more than eight times as frequently after an extracapsular than after an intracapsular cataract extraction. The visual acuity results after discussion were uniformly good. Transpars plana vitrectomy was reserved for more severe cases. The pupils were cleared, but the visual acuity results were mixed. A fluorescein angiographic study revealed little difference in the incidence of cystoid macular edema in implant and nonimplant cases. There was a lower incidence after extracapsular than intracapsular extractions in implant cases.