Clinical outcome of intravitreal gentamicin injection for the treatment of end-stage glaucoma in five rabbits (eight eyes)

Abstract

Background: glaucoma is a painful and blinding condition that occurs in many species, including rabbits. When medication is no longer effective in maintaining the intraocular pressure, enucleation is the recognised treatment for rabbits with end stage glaucoma. However, this procedure carries risks relating to the procedure and the anaesthesia. Aim: The aim of this retrospective study was to report the efficacy of intravitreal gentamicin injection in controlling intraocular pressure in blind eyes of rabbits with end-stage glaucoma. Ocular and nonocular complications were retrospectively assessed. Methods: Medical record review was performed to identify five client-owned rabbits (eight eyes) that were treated by intravitreal injection of 6-20 mg of gentamicin per eye (median 7.18 mg/kg) for chronic, end-stage glaucoma. Treatment was unilateral in two and bilateral in three rabbits. Intraocular pressure control was assessed via rebound tonometry readings performed approximately two weeks, one month, three months and six months after injection. Total follow up was between 313-1111 days. Ocular complications were recorded and systemic health was estimated by the owner-answered questionnaire and changes in body weight. Results: Intraocular pressure was <25mmHg in 87.5% of eyes three months post injection. The most common ocular complications were cataracts (62.5%), anterior uveitis (25%), retinal detachment (12.5%) and corneal erosion (12.5%). There were no behavioral or body weight changes suggestive of systemic complications. Conclusion: 87.5% of rabbit eyes treated with intravitreal gentamicin had controlled intraocular pressure three months after injection. All eyes were blind at the time of injection. Ocular side-effects were common. Investigation of safety and systemic effects of intravitreal gentamicin injection is required, however no overt complications were identified in treated rabbits in this study.