Clinical and biological evaluations of biodegradable collagen matrices for glaucoma drainage device implantation

PURPOSE. To characterize the clinical and biological properties of biodegradable collagen matrices (BCMs) for possible glaucoma drainage device implantation. METHODS. A total of 68 refractory glaucoma eyes, followed up postoperatively for at least 6 months, were consecutively enrolled after retrospective chart review. The BCM-augmented Ahmed valve implantations (BAAVI) using our Ologen-6 and Ologen-7 valves were performed and compared with a conventional method. Complete surgical success was defined as an IOP of ≤21 mm Hg (IOP 1) or ≤17 mm Hg (IOP 2) without antiglaucoma medications. Qualified success was defined as an IOP ≤21 mm Hg with or without antiglaucoma medications. The biological properties of each BCM were assessed by enzymatic degradation rates via collagenase under ocular physiological conditions. RESULTS. The mean ages and preoperative IOPs were similar for the groups. In the conventional, BAAVI with Ologen-6, and BAAVI with Ologen-7 groups, complete success rates with target IOP 1 were 29.2%, 40.0%, and 66.7%; those with target IOP 2 were 12.5%, 30.0%, and 45.8%; qualified success rates were 45.8%, 55.0%, and 75.0%, respectively. The enzymatic degradation rate of Ologen-7 was significantly slower than that of Ologen-6 (12.5 3 10^-3 vs. 28.8 3 10^-3). CONCLUSIONS. The surgical success rate was highest in the Ologen-7 BAAVI group, with the lowest dependency on postoperative antiglaucoma medication use compared with the conventional and Ologen-6 BAAVI groups. The clinical results correlated with the different biological and physicochemical properties based on the degree of enzymatic degradation and on the structural morphology.