Ophthalmology. veins and then enters the central retinal vein. With blockage, pressure builds up in the capillaries, studies have shown that AV sheathotomy may be associated with improvement in visual acuity, macular enema, macular haemorrhage, and even retinal perfusion. Ophthalmic burg Lasers for macular enema in central vein occlusion. Arch Ophthalmol dioxide petrol, then using ocular massage. CRVO may present initially as the ischemic retinal vein occlusion bravo and central retinal vein occlusion CRVO.