Materials and Methods: Medical records of 54 patients diagnosed with retinal vein occlusion (RVO) and 47 age and sex matched individuals as control group were reviewed retrospectively. ABO(H) blood groups, Rh factors, the history of diabetes mellitus, hypertension, smoking, deep venous thrombosis, or cerebrovascular occlusion were recorded. All patients were divided into two subgroups; patients with central retinal vein occlusion (CRVO, n=22) and patients with branch retinal vein occlusion (BRVO, n=32). The frequencies of ABO (H) blood groups, Rh factors and other parameters in RVO group, CRVO and BRVO subgroups were analyzed statistically.

Results: The frequency of non-O blood groups was statistically higher in RVO group than control group (p?0.017, OR: 0.37 CI: 0.16-0.84). Although the frequency of A and B blood groups were statistically higher in RVO group, there was no significant difference in AB blood group between RVO and control group. The frequency of non-O blood groups was insignificantly higher in BRVO subgroup whereas non-O blood groups were significantly higher in CRVO subgroup (p?0.015). The distribution of Rh groups was not statistically different in all groups. Moreover there was no statistically significant difference in ABO(H) (p?0.160, OR: 2.71 CI: 0.65-11.24) and Rh groups between CRVO and BRVO subgroups.

Conclusion: Having a non-O blood group can be associated with an increased risk of RVO. Keywords : Retinal vein occlusion, ABO blood-group system