crvo and brvo risk factors

introduction :   branchretinal vein occlusion (brvo), in which one of the branches of the main vein are blocked, andcentral retinal vein occlusion (crvo) in which the main vein of the eye is blocked    often occur  in elderly people and are the second to diabetes in producing disease of the vessels of the retina. the main causes of vein occlusions in middle and young aged population is not well understood.  this study investigated the most important causes of central and branch retinal vein occlusions. materials & methods: 20 patients aged under 50 with brvo and crvo referred to imam khomeini hospital  in kermanshah during 1999-2003 were studied. brvo and crvo were diagnosed by ophthalmologist and subjects referred to internal specialist for further investigations on systemic diseases. result: the most common associated diseases found in these patients were hypertension, hyperlipidemia and diabetes. there was not any mentioned causes in one of these patients. in brvo patients, 8 eyes (72.7%) with supratemporal involvement, one eye (9.1%) with inferonasal involvement, and four eyes (36.4%) with inferotemporal involvement were found, however no eyes were found with superatemporal involvement.  conclusion: even though hyperlipidemia reported less common causes vein occlusions in elderly, we can conclude that hypertension and hyperlipidemia were two most common causes in brvo and crvo diseases among young population.