Homocysteine in Retinal Vascular Occlusions

Elevated plasma homocysteine (hcys) has been associated with a greater risk of heart disease and stroke. A number of studies have suggested that hcys may be a contributing factor to development of various ocular disease. Central retinal vein occlusion (CRVO) is one of the most common vision-threatening retinal vascular diseases, affecting primarily elderly patients. Several studies have demonstrated elevated hcys levels to be a potential risk factor in CRVO, but others failed to find such an association. Also, value of treating an elevated plasma hcys with folic acid for preventing further disease has not been proven. Although secondary prevention of coronary artery disease using this approach has been unsuccessful, trials on primary prevention of stroke and loss of cognitive function with folic acid supplementation appear to be successful. Further trial data are awaited. In this article we will review how systemic and local production of hcys might contribute to the pathogenesis of Retinal Vascular Occlusions.