Introduction: The aim of the study was to estimate the phenotypeof retinal vessels using CRAE (central retinal artery equivalent), CRVE (central retinal vein equivalent), tortuosity and fractal analysis in the unaffectedcontralateral eye of patients with central (CRVO) or branch (BRVO) retinal vein occlusion. Methods: 34patients suffering from CRVO, 15suffering from BRVOand 49 controlled-matched subjects had a fundus image analyzed using the VAMPIRE software. The intraclass correlation coefficient and a Bland-Altman plot were done for the reproducibility study.Results: There was a lack of evidence of differencebetween the control group and the CRVO group for CRAE (p=0.06), CRVE (p=0.3) and arterio-venule ratio(AVR, p=0.6).Contralateral eyes of CRVO exhibited a significantly higherarterial and minimum arterial tortuosity values (p=0.012), as compared with control eyes. Contralateral eyes of patients with ahistoryof BRVO had a significantly higherCRAE (p=0.02), AVR (p=0.006) and minimal arterial tortuosity (p=0.05). Fractal analysis showed that contralateral eyes of BRVO had higher values of fractal parameters(D0a, p=0.005).Conclusion: This study suggests that CVRO or BRVO are not triggered by the same retinal vascular phenotypes in the contralateral eye. The morphology of retinal vasculature may be associated with the occurrence of RVO, independentlyof known risk factors.