Changes in Corneal Endothelial Cells after Ahmed Glaucoma Valve Implantation: 2-Year Follow-up

PurposeTo evaluate changes in corneal endothelial cells after Ahmed glaucoma valve (AGV) implantation for the treatment of refractory glaucoma.DesignObservational case series.MethodsWe prospectively evaluated the change in density and shape of the corneal endothelium in 41 patients (41 eyes) who had undergone AGV implantation for the treatment of refractory glaucoma. Corneal specular microscopy was performed on the superior, supratemporal, supranasal, and central areas with a noncontact specular microscope before surgery and 1, 6, 12, 18, and 24 months after surgery. The changes at each time point were compared with those at baseline and with those of the control group, which consisted of 20 contralateral glaucomatous eyes receiving antiglaucoma medications.ResultsThe mean follow-up was 19.1 months. The average percentage decrease in corneal endothelial cell count was 5.8% at 1 month, 11.5% at 6 months, 15.3% at 12 months, 16.6% at 18 months, and 18.6% at 24 months after surgery. The changes were statistically significant compared with those at baseline and those of the control eye at all time points during the study period (P < .05). The supratemporal area, the closest site to the tube, showed the greatest decrease in endothelial cell density, by 22.6%, whereas the central cornea showed the smallest decrease, by 15.4%, at 24 months after surgery.ConclusionsThere was statistically significant corneal endothelial cell loss in the operated eye after AGV implant surgery. The corneal endothelial cell loss increased with time: 15.3% at 12 months and 18.6% at 24 months after surgery, on average, in all measured areas.