Scleral avulsion after Ahmed valve M4 removal.

We report a case of intraoperative scleral avulsion that occurred during explantation of an Ahmed M4 valve. A 79-year-old female with open angle glaucoma with a history of glaucoma drainage device (GDD) implantation presented for routine follow-up. The ophthalmic examination indicated a focal implant exposure. The patient was scheduled for explanation of tube and plate and placement of alternate GDD. During implant removal, a horse-shoe shaped scleral avulsion was noted with softening of the globe and uveal and vitreous prolapse. The case was converted to an open globe repair and further glaucoma intervention was deferred. The vitreoretinal service was consulted, and glaucoma drops were added as needed to control intraocular pressure. Removal of Ahmed M4 implant can carry the risk of intraoperative scleral avulsion.