The medical records of 90 patients with a clinical diagnosis of retinal vein occlusion (RVO) who were seen at two referral hospitals in Saudi Arabia were reviewed. Sixty-eight (75.6%) were men. Central RVO was present in 50 patients (55.6%); branch RVO, in 35 patients (38.9%); and hemiretinal occlusion, in five patients (5.6%). Arterial hypertension was present in 43 patients (47.8%); diabetes mellitus, in 28 patients (31%); and preexisting glaucoma, in 26 patients (28.9%). The date of onset of RVO was available in 61 patients. Eighteen attacks (29.5%) had occurred during the month of Ramadan. The Student's t test of paired samples indicated that the incidence of RVO during the month of Ramadan was significantly higher than that of the other months of the Gregorian year. These findings suggest that dehydration may play a role in the pathogenesis of RVO.