An Evaluation of Intravitreal Ranibizumab for Vitreous Hemorrhage Due to Proliferative Diabetic Retinopathy

In mild to moderate cases of vitreous hemorrhage, panretinal photocoagulation (PRP) is performed when possible to achieve regression of new vessels or at least stabilization of the neovascularization with no further growth in order to decrease the probability of subsequent vitreous hemorrhage while spontaneous absorption of the hemorrhage occurs. In cases in which the hemorrhage is too dense to apply PRP, vitrectomy is considered to remove the hemorrhage and provide a clear media for application of PRP (often as endolaser photocoagulation) as well as eliminate extensive neovascularization and relieve traction retinal detachments. Pars plana vitrectomy was introduced in the 1970s as a surgical intervention in diabetes for non-clearing vitreous hemorrhage, traction retinal detachment or very severe proliferative diabetic retinopathy (PDR). The goal of vitrectomy in such eyes is to remove the hemorrhage and provide a clear media for application of PRP (often as endolaser photocoagulation) as well as eliminate extensive neovascularization and relieve traction retinal detachments. Many advances in instrumentation and technique have resulted in a dramatic reduction in complications over the last few decades, but surgical complications remain including the following: neovascular glaucoma, retinal detachment, fibrinoid syndrome, endophthalmitis and hypotony with subsequent phthisis bulbi. Recovery for the subject can take up to 6 weeks.

Increased vascular endothelial growth factor (VEGF) levels have been demonstrated in the retina and vitreous of human eyes with diabetic retinopathy, especially PDR. VEGF has been demonstrated to increase vessel permeability by increasing the phosphorylation of tight junction proteins, and has been shown to increase retinal vascular permeability in in vivo models. Anti-VEGF therapy, therefore, may represent a useful therapeutic modality which targets the underlying pathogenesis of PDR while vitreous hemorrhage clears to facilitate the placement of PRP, potentially avoiding vitrectomy.

This study is designed to determine if intravitreal injections of ranibizumab will facilitate clearing of vitreous hemorrhage and avoidance of vitrectomy and its potential complications. Compared with a surgical intervention, use of an intravitreal agent associated with fewer vitrectomies would be preferable because of the reduced costs, reduced time to treatment, reduced intervention time, relatively low risk of side effects, and reduced recovery time. An intravitreal agent also would be a useful alternative for patients who are unwilling to undergo surgery. Furthermore, the study will determine the safety of this medication in the setting of PDR.