PURPOSE: To compare the safety and efficacy of human preserved amniotic membrane transplant with conjunctival advancement for repair of late-onset glaucoma filtering bleb leaks. METHOD: A prospective, randomized clinical trial com pared amniotic membrane transplant with conjunctival advancement in patients with leaking glaucoma filtering blebs, Intraocular pressure, number of glaucoma medications, and reoperation for glaucoma or persistent or recurrent bleb-leak were compared in the two groups, Patients were followed for a minimum of 1 year. RESULTS: Mean intraocular pressure was the same at 6 (amniotic membrane transplant, 15.4 +/- 4,4, conjuncti val advancement 14.1 +/- 6,4, P = 0.6), 12 (amniotic membrane transplant, 15.0 +/- 6.3, conjunctival advancement, 13.2 +/- 6.6, P = 0.5), and 24 (amniotic membrane transplant, 17.2 +/- 7.1, conjunctival advancement, 15.0 +/- 6.3, P = 0.6) months, The mean number of glaucoma medications in use was the same in the two groups at all time intervals. After an average follow-up of 19 months, there were seven failures in the amniotic membrane transplant group (two with persistent leaks that were unresponsive to further suturing, two with late-onset leaks, and three who required repeat glaucoma surgery) and none in the conjunctival advancement group, The cumulative survival rate for amniotic membrane transplant was 81% at 6 months, 74% at 1 year, and 46% at 2 years. The cumulative survival rate was 100% for conjunctival advancement throughout follow-up. CONCLUSIONS: Amniotic membrane transplantation does not offer an effective alternative to conjunctival advancement for repair of leaking glaucoma filtering blebs. (C) 2000 by Elsevier Science Inc. All rights reserved.