PURPOSE: To describe hypotony caused by erosion of the conjunctiva and sclera by a silicone scleral buckle. METHODS: Interventional case report. A 33-year-old man with Marfan syndrome presented with hypotony maculopathy and a collapsed globe 17 months after repair of retinal detachment with a silicone sponge and silicone encircling band. RESULTS: Examination in the operating room revealed extrusion of the buckle through the conjunctiva and full-thickness scleral erosion. The silicone buckle was removed, and the scleral defect was closed with interrupted 8-0 nylon sutures. Postoperative glaucoma was treated with cyclophotocoagulation. Eight months after scleral repair, visual acuity was RE: 20/40, intraocular pressure was 10 mm Hg, and the retina was attached. CONCLUSION: Full-thickness scleral erosion secondary to a silicone exoplant causing hypotony is a rare long-term complication in patients with thin sclera.