Surgical repair of tube exposure with limbal insertion of Ahmed glaucoma valve

We report the management and surgical repair of an exposed Ahmed glaucoma valve (AGV) tube with limbal necrosis. A middle-aged male with a history of AGV implantation in the right eye and trabeculectomy in the left eye presented with tube exposure in the right eye. The exposed tube was found to be entering the anterior chamber through a corneal entry, causing limbal thinning and necrosis. Worsening conjunctival and limbal necrosis around the exposed tube was noted, necessitating surgical intervention. The procedure involved tube repositioning with an oblique entry at a different site, scleral patch graft reinforcement with fibrin glue, closure of the limbal wound, and conjunctival autograft advancement. Postoperative care included systemic doxycycline, topical steroids, and antibiotics. The patient had a stable postoperative course with the conjunctival and scleral grafts healing well. Intraocular pressure (IOP) was 10 mm Hg on day 1, rising to 32 mm Hg at one month, then stabilizing at 21 mm Hg at 6 weeks with three antiglaucoma medications. The tube remained covered with no evidence of exposure or infection. Corneal entry of glaucoma drainage devices can cause progressive conjunctival and limbal necrosis, causing tube exposure, which can pose significant surgical challenges.