Corneal Endothelial Cell Damage from Glaucoma Drainage Device Materials

PURPOSE: To compare the level of endothelial damage caused by contact with materials used in contemporary glaucoma drainage devices and a phosphorylcholine polymer-coated PMMA (PC-PMMA). METHODS Standard-sized discs of silicone, PMMA (polymethylmethacrylate), and PC-PMMA (n = 6) were gently lowered onto cultured bovine corneal endothelial (BCE) monolayers using a vacuum suction device. A 2.4-g stainless steel cloning ring weight was then placed on top of each disc. The weights and discs were removed using a vacuum suction device and forceps after 5 minutes of contact. A 0.4% trypan blue solution was used to stain the cell monolayer to visualize the area of cell damage. The total area of damage in each well (including the area stripped of cells) was measured using an image processor and expressed as a percentage of the total disc area to derive a damage coefficient for each material. Damage coefficients for different materials were compared using Bonferroni corrected analysis of variance (ANOVA). RESULTS: Percentage of areas of damage (mean +/- SD) after standardized contact were as follows: PMMA, 5.95 +/- 4.60%; silicone, 3.08 +/- 2.68%; PC-PMMA, 0.15 +/- 0.25%. PMMA caused marked endothelial cell damage. PC-PMMA discs produced a significantly lower level (p = 0.04) of endothelial cell trauma. CONCLUSION: Our results suggest that PC coating technology may be effective in reducing the rate of corneal endothelial failure following GDD implantation.