Bleb morphology and histology in a rabbit model of glaucoma filtration surgery using Ozurdex® or mitomycin-C

PURPOSE To determine the effect of a sustained-release dexamethasone implant (Ozurdex(®)) on wound healing after glaucoma filtration surgery in a rabbit model. METHODS Twelve new zealand white rabbits were divided into three groups: filtration surgery with intraoperative subconjunctival implantation of Ozurdex(®) (n=6), filtration surgery with intraoperative topical application of mitomycin-C (MMC; n=6), and filtration surgery with intraoperative topical application of balanced salt solution (BSS; n=12). A standard scale was used to grade bleb vascularity at three and six weeks after the initial operation. Bleb survival was also recorded for comparison between the three groups. Histologic analysis was performed with attention to cellularity and collagen deposition. RESULTS MMC-treated blebs demonstrated decreased numbers of goblet cells compared to all other groups. Blebs treated with Ozurdex(®) maintained a near normal number of goblet cells with modest collagen deposition. The control eyes treated with only BSS had significant collagen deposition and increased cellularity compared to both the Ozurdex(®) and MMC groups. Bleb vascularity was not significantly different among groups at the three and six week post-operative evaluations. MMC-treated and Ozurdex(®)-treated blebs had significantly prolonged bleb survival compared to blebs treated with only BSS. In addition, MMC-treated blebs had significantly longer survival compared to Ozurdex(®)-treated blebs. CONCLUSIONS The results of this study support the utility of extended-release dexamethasone (Ozurdex(®)) as a wound modulating agent in a rabbit model of filtration surgery. Further animal and human studies are needed to better characterize a possible role for Ozurdex(®) in filtration surgery.