Changes of corneal endothelial cell density after EX-PRESS® Glaucoma shunt implantation: 2-year follow-up study

Purpose: To evaluate effects of the EX-PRESS® glaucoma filtering device on the corneal endothelial cell density (ECD) in eyes with open angle glaucoma (OAG). Designs: A prospective, non-comparative study. Methods: We prospectively evaluated the changes in the ECD, hexagonality, and coefficient of variation (CV) in 20 eyes of 19 patients who had an implantation of the EX-PRESS®. The type of glaucoma was exfoliation glaucoma in 6 eyes, uveitic glaucoma in 5 eyes, secondary glaucoma following vitrectomy in 4 eyes, primary OAG in 3 eyes, and neovascularization glaucoma in 2 eyes. Corneal specular microscopy was performed at the central cornea before, 1, and 2 years after the EXPRESS® implantation. Results: The mean ECD was 2008 cells/mm2 before the surgery, 1956 cells/mm2 at 1 year, and 1846 cells/mm2 at 2 years after the surgery which represent a decrease of 5.0% at 1 year and a further decrease of 9.4% at 2 years. The decrease in the ECD from baseline to 1 year was not statistically significant, however the decreases from the baseline to 2 years (P<.0001) and from 1 year to 2 years (P=.0001) were significant. There was a significant change in the CV between the baseline and 1 year (P=0.03), and the change between baseline and 2 years was close to a statistically significant difference (P=0.07). There was no significant change in hexagonality during the 2 years. Two eyes with low preoperative ECD had a marked decrease in the ECD at 2 years. Conclusions: There is a slow decrease in the ECD after the EX-PRESS® implantation.