Collateral Circulation in the Branch Retinal Vein Occlusion

Kang, Ki Tae; Kim, Young Joon

Abstract

Collateral circulation that develops in the chronic stage of branch retinal vein occlusion (BRVO) was known to affect the cliniral course of this disease. To study the development of collateral circulation according to the types of BRVO, 45 eyes with BRVO in which fluorescein angiographies(FAG) were taken more than two times were divided into 3 groups by the combination of the area of capillary non perfusion and the amount of cotton wool patches. Group I showed a small area of nonperfusion, group II, a wide-spread nonperfusion area with no or several cotton wool patches and group III, a wide-spread nonperfusion area with predominant cotton wool patches. The collateral and the venovenous anastomosis was further subdivided into high-low anastomosis, bridging vessel and recanalization. Then we compared the incidence of collateral vessels in each group. As a result, in group II and III, higher incidence of arteriovenous anastomosis, arteriovenous and venovenous anastomosis was recognized compared to group I. In the cases of major temporal vein occlusion, higher incidence of arteriovenous anastomosis compared to the cases of macular branch vein occlusion. And in group III, higher incidence of neovascularization was found compared to group I.