ABSTRACT
The retinal blood bessels exit the optic disc and branch in a complex pattern to serve the metabolic need of the inner retina. As the vessels traverse the retina, the arteries and veins frequently cross one another. Recently, there has been renewed iterest in the orientation of the crossing retinal vessels at arteriovenous intersections, particularly as it relates to the risk of branch retinal vein occlusion. The authors studied standard fundus photographs of 30 subjects(60 eyes) who don't habve any retinal and systemic disorders. Arteriovenous crossings were analized for fundus location and relative orientation of the crossing vessels(vein-posterior or vein-anterior). In the superotemporal quadrant, A-V crossings were a greater number, distributed closer to the optic disc than the inferotemporal quadrant. Also a greater proportion of crossings was vein-posterior than the inferotemporal quadrant. These findings may explain the predilection for branch retinal vein occlusions to occur frequency in the superotemporal quadrant.