Purpose To examine the vascular density in different retinal layers and in the choriocapillaris in eyes with retinal vein occlusions (RVO). Methods Applying optical coherence tomography angiography (OCTA), we examined patients with unilateral RVOs and normal individuals of a control group. Results The study group included 48 patients with unilateral RVO and the control group 17 normal individuals. Eyes affected by RVO as compared to the contralateral unaffected eyes (all P < 0.001), and the contralateral unaffected eyes as compared to the eyes of the control group (P < 0.05), showed a lower vessel density in the superficial and deep retinal layers in all regions except for the foveal region. Choriocapillaris density was lower (P < 0.001), foveal retinal thickness and subfoveal choroidal thickness (P < 0.001) were thicker, and the foveal avascular zone was larger (P = 0.003) in the RVO eyes than in the contralateral eyes. For 29 eyes undergoing OCTA and fluorescein angiography, two examiners independently rated the retinas to be ischemic in fluorescein angiography in 14 eyes and in OCTA in 9 of these 14 eyes. Conclusions Upon OCTA, unaffected eyes of patients with unilateral RVOs showed vascular abnormalities in the superficial and deep retinal layers when compared to those of healthy individuals.