I observed transient membrane formation consisting primarily of fibrin on the anterior surface of the IOL in 45 (7.6%) of the 596 eyes that received posterior chamber lens implantation during the past year. The onset of the condition was generally five to six days after surgery. This membrane characteristically developed between the margins of the anterior capsule, and therefore might be the result of lens-induced uveitis from the proliferation of lens epithelial cells under the anterior capsule.