Original Article Hyperhomocysteinemia, a Biochemical Tool for Differentiating Ischemic and Nonischemic Central Retinal Vein Occlusion during the Early Acute Phase

Purpose: The purpose of the study was to differentiate ischemic central retinal vein occlusion (CRVO) from non-ischemic CRVO during the early acute phase using plasma homocysteine as a biochemical marker. Methods: Fasting plasma homocysteine, serum vitamin B12, and folate levels were measured in 108 consec-utive unilateral elderly adult (age>50 years) ischemic CRVO patients in the absence of local and systemic disease and compared with a total of 144 age and sex matched nonischemic CRVO patients and 120 age and sex matched healthy control subjects. Results: Homocysteine level was significantly increased in the patients with ischemic CRVO in comparison with nonischemic CRVO patients (p = 0.009) and also in comparison with control subjects (p < 0.001). Analysis also showed that hyperhomocysteinemia was associated with increased incidence of ischemic CRVO (odds ratio, 18) than that for nonischemic CRVO (odds ratio, 4.5). Serum vitamin B12 and folate levels were significantly lower (p < 0.001) in CRVO patients compared to the control but were not significantly different between nonischemic and ischemic CRVO patients (p> 0.1). Conclusions: Hyperhomocysteinemia can be regarded as useful in differentiating nonischemic and ischemi