The Inflammatory and Foreign Body Reaction of Polymethyl Methacrylate Glaucoma Drainage Device in the Rabbit Eye

Purpose To assess the safety and tissue response of a polymethyl methacrylate (PMMA) glaucoma drainage device (GDD) in the rabbit eye. Methods Specially constructed PMMA GDD devices were implanted into rabbit eyes and evaluated histopathologically following euthanasia on days 5, 30, and 60 after implantation surgery. Hematoxylin-eosin, Masson's trichrome, and periodic acid-Schiff were used to stain tissue specimens dissected from the surgical site. Inflammatory cell count and capsule thickness measurements were performed. Results Three rabbits were sacrificed on day 5, 3 on day 30, and 4 on day 60. Macrophage and lymphocyte counts increased from day 5 to day 30 then decreased (P = 0.0000) with greater counts seen in the superior regions. At day 30, a fibrous capsule had formed around the plate area. Fibroblast counts increased significantly between day 5 to day 30 and again to day 60 (P = 0.001) with greatest numbers anteriorly. The inferior capsule thickness at day 60 was 243 µm (standard deviation, 120; 95% confidence interval: 53-433). The superior capsule thickness was 388 µm (standard deviation, 136; 95% confidence interval: 172-604). No adverse reactions were seen. Conclusions Histopathologically, the inflammatory response toward this PMMA glaucoma drainage device was comparable to other reported GDDs. No accentuated response or adverse event was seen suggesting that PMMA may be useful as a GDD material. Translational Relevance An affordable, locally built GDD is needed in Indonesia because of the high prevalence of severe glaucoma. This rabbit study is a significant step toward justifying the use of PMMA as a GDD material. PMMA is cheap and easily manufactured and sterilized in developing economies.