Formation of Collateral Vessels and New Vessels in Branch Retinal Vein Occlusion

Abstract

Purpose: To study the development of collateral vessels and new vessels according to the types of branch retinal vein occlusion (BRVO). Methods: One hundred and nine eyes of 103 patients with branch retinal vein occlusion were divided into 4 groups by anatomical position of blockage site and pattern of neovascularization. fluorescein angiography was used to examine perfusion/ nonperfusion, size of obstruction site, distance between obstruction site and optic disc (or macula). We compared initial visual acuity and final visual acuity. Results: there was no statistically significant difference between group in size, between the obstruction site and the optic disc, between the obstruction site and macula. Collateral vessels occurred in major vessel obstruction (MVO) and major vessel and macula obstruction (MVMO) more than in macula obstruction (MO) and peripheral vessel obstruction (PV). Collateral vessels occurred 50 eyes in patients with macula edema and new vessels occurred 36 eyes in patients with macula edema. In collateral group, there was higher incidence of collateral vessels in ischemic type compared to nonischemic type and higher incidence of collateral vessels after laser photocoagulation. ischemic group with collateral vessels had better visual acuity prognosis than perfusion group with collateral vessels. Conclusions: collateral vessels in BRVO have a favorable effect on visual prognosis. If patients with collateral vessels shows ischemic type, macula edema and involvement of first order, early laser photocoagulation is recommended for visual prognosis.