Changes in corneal endothelial cell density and morphology after Ahmed glaucoma valve implantation during the first year of follow up

Purpose: To determine the effect of Ahmed glaucoma valve (AGV) implantation on corneal endothelial cells. Methods: Ahmed glaucoma valves were implanted in 30 eyes of 30 patients with refractory glaucoma. Corneal endothelial cell density and shape was prospectively evaluated in both the subject and fellow eyes of each patient. Corneal specular microscopy was performed on the superior, superotemporal, superonasal and central corneal areas before and at 1, 6 and 12 months after surgery. Results: A statistically significant decrease in average corneal endothelial cell density was observed 12 months postoperatively in the subject eyes compared with the baseline value (P = 0.001). No such changes were observed in the fellow eyes during follow-up period. The mean percentage decrease in corneal endothelial cell density in subject eyes was 3.5% at 1 month, 7.6% at 6 months and 10.5% at 12 months after surgery. The superotemporal area, which was closest to the tube, showed the greatest decrease in endothelial cell density at 1 year after surgery, while the central cornea showed the least decrease. In terms of endothelial cell morphology, polymegathism and pleomorphism increased in the early postoperative periods, and then gradually approached the preoperative status by 6 months after surgery. Conclusion: Corneal endothelial cell density progressively decreased after AGV implantation. These findings indicate that particular care should be taken during intraoperative and postoperative management of AGV implantation patients in order to minimize damage to the endothelium.