Evaluation of an aqueous drainage glaucoma device constructed of ePTFE

Aqueous drainage devices for the treatment of glaucoma are subject to the s ame limitations as most polymeric implants, namely a healing response compr ised of chronic inflammation and fibrosis, The most widely used devices are currently made of silicone or polypropylene, materials that exhibit biocom patibility difficulties when they are implanted on the sclera underneath th e conjunctiva of the eye, Decreased outflow of aqueous fluid to the conjunc tival space caused by the development of a fibrous capsule around the devic e accounts for at least 20% of aqueous shunts failures. Clearly, the need e xists to improve the healing response to aqueous drainage devices, and one approach is to develop new polymers or polymer modifications. Improved devi ces would elicit a limited fibrotic response while increasing neovasculariz ation around the implant, Previous studies have indicated that denucleation markedly improves the healing characteristics and biocompatibility of expa nded polytetrafluoroethylene (ePTFE), We reasoned that altering the design of drainage devices to allow the use of denucleated ePTFE irt vivo might mi nimize fibrosis, thereby improving shunt function. We found that after 8 we eks in vivo, experimental shunt function was equivalent to the Baerveldt sh unt, while there was less scarring with increased neovascularizatin, These findings suggest that ePTFE has potential as an improved, long-term alterna tive material for use in constructing glaucoma shunts. (C) 1999 John Wiley & Sons, Inc.