Novel synthetic meshwork for glaucoma treatment. I. Design and preliminaryin vitro and in vivo evaluation of various expanded poly(tetrafluoroethylene) materials

A novel drainage implant for glaucoma filtering surgery (MESH) is proposed. After various expanded poly (tetrafluoroethylene) (e-PFTE) materials were evaluated, the feasibility and the short-term safety of the technique were assessed in this first pilot study in the rabbit. The porous structure and the in vitro resistance to aqueous flow of seven different e-PTFE membranes (5-80 mu m average pore size) were compared. Eight Dutch pigmented rabbits were implanted with the T-shaped MESH implants made from either 20- or 50- mu m average pore size e-PTFE membranes. Clinical examination, intraocular pressure (IOP) measurements, and histology analyses were performed over a p eriod of 3 months. The contralateral nonoperated eyes served as controls. M ESH implantation took less than 7 min. No post-operative hypotony, migratio n, or extrusion of the implant and no intraocular inflammation or infection occurred. A significant IOP reduction in the implanted eyes was obtained p ast postoperative day 21 with the 20-mu m material implant. The drainage ef ficacy was correlated with the degree of colonization of the porous materia ls and the inner spacing of the implant as observed by histology. With a fi ltering patency 3 times longer than conventional trabeculectomy and laser s clerectomy, MESH surgery is a promising technique for glaucoma treatment. F urther studies are underway to enhance the device efficacy and understand t he mechanism of filtration. (C) 1999 John Wiley & Sons, Inc.