The Use of Bioerodible Polymers and Daunorubicin in Glaucoma Filtration Surgery

Abstract

Purpose: Glaucoma filtering surgery usually fails from postoperative fibroblast proliferation, collagen deposition, and subsequent sclerostomy or bleb scarring. Daunorubicin inhibits fibroblast proliferation in vivo and in vitro. The authors studied the effect of a sustained subconjunctival release of daunorubicin by way of a bioerodible polymer on the success of glaucoma filtration surgery in a rabbit model.Methods: Daunorubicin was incorporated into the copolymer by compression molding. The resultant implant measured 3.0 mm in diameter, 1.0 mm in thickness, and 8.0 mg in weight. A posterior lip sclerectomy was performed in both eyes of 23 rabbits by the same surgeon. One eye was randomized to receive the disc with daunorubicin, whereas the fellow eye received a blank disk as a control. The appropriate polymer disk then was placed on the scleral surface immediately posterior to the sclerostomy site and the conjunctiva was closed. Intraocular pressures and slit-lamp biomicroscopy were recorded preoperatively, then every other day after surgery for 31 days. Intraocular pressure, bleb survival, and complications were evaluated.Results: The decrease in intraocular pressure from baseline was significantly greater in the daunorubicin eyes than in the control eyes during postoperative days 5 through 25. Bleb survival was significantly longer in the daunorubicin eyes than in the control eyes (bleb failure in 91% of control eyes versus 22% of treatment eyes by day 13). There were no statistically significant differences between the daunorubicin-treated and control eyes regarding corneal clouding, lens clarity, cataract formation, or conjunctival injection. However, conjunctival erosions occurred in four daunorubicin-treated eyes. Histopathologic examination was performed 2 weeks after surgery on the eyes of three randomly selected rabbits.Conclusion: Daunorubicin in a bioerodible delivery system may potentially be a useful adjunct to glaucoma filtering surgery and requires further evaluation.