Retinal venous occlusion and ABO blood-groups.

The distribution of ABO blood-groups in 79 patients with a retinal venous occlusion (RVO) was not significantly different from that of local blood donors. In 67 of these patients it was found that the visual outcome six months after the RVO is significantly associated with the patient's ABO blood-group. For central and branch retinal vein occlusions taken together 18 percent of patients with blood-group A had a vision of 6/9 or better in the affected eye, whereas 46 percent of patients with blood-group 0 and 49 percent of patients with blood-groups, O, B or AB achieved this vision.