Description:
Branch retinal vein occlusion (BRVO) is the second most common retinal vascular disease after diabetic retinopathy. It results from a blockage of the part of the circulation that drains blood from the retina.
Symptoms of BRVO include peripheral visual loss, distortion of vision, or 'blind spots'. In some cases spontaneous improvement in vision can occur as the macular oedema (which follows acute occlusion of the vein) resolves.
BRVO typically occurs at arteriovenous crossings, where the artery and vein share a common adventitial sheath. Arteriovenous crossing sheathotomy is commonly used as an adjuvant to pars plana vitrectomy.
In arteriovenous sheathotomy, the overlying artery is separated from the vein with a microvitreoretinal blade. A pars plana vitrectomy is first performed (surgical removal of the vitreous). An incision is then made in the adventitial sheath adjacent to the arteriovenous crossing, and is extended along the membrane that holds the blood vessels in position to the point where they cross. At this point, the blade is used to separate adhesions holding the artery to the vein. The artery is then lifted away from the vein.
Cutting the sheath around the vessels and physically separating them where they cross should improve blood flow through the vein.
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