Purpose: To determine whether a synthetic material, expanded polytetrafluoroethylene (E-PTFE), can be used successfully as a reinforcement material over the tubes of glaucoma drainage implants.
Methods: Patches of E-PTFE were sutured over the tubes of Baerveldt glaucoma drains implanted in the eyes of New Zealand white rabbits. Two material thicknesses were tested: 0.5 mm in four eyes and 0.25 mm in five eyes. Rabbit donor scleral patches were used in five eyes as the control. Total ocular health and intraocular pressure were monitored every 2 weeks after the procedure. Six months after implantation, the eyes were harvested and analyzed histologically.
Results: Two of the four eyes that received 0.5-mm thick E-PTFE patches showed some conjunctival melting over the anterior corners of the material close to the limbus. All five eyes that received 0.25-mm thick E-PTFE patches showed a healthy cellular wound healing response and no conjunctival melting. Cellular infiltration and collagen deposition in the E-PTFE materials showed integration of the patch material into the surrounding tissue. In the control eyes, marked thinning and resorption of the donor sclera immediately above the drainage tube was noted.
Conclusion: Thin (0.25 mm) E-PTFE patches were well tolerated in all rabbit eyes tested. Thin E-PTFE should be investigated further as a functional alternative to donor sclera for reinforcement in glaucoma drain surgery.