Abstract The development of a retinal vein occlusion (RVO) is multifactorial. This study investigates pachychoroid as a risk factor for RVO or as an entity sharing common pathophysiology with RVO. A database screening at the University Eye Hospital, Ludwig-Maximilian University Munich, Germany was performed for patients diagnosed with central or branch RVO (CRVO/BRVO). In every patient a complete ophthalmologic examination was performed, including posterior segment enhanced depth spectral domain optical coherence tomography (EDI-SD-OCT). The SD-OCT scans of respective partner eyes without history of RVO were compared to an age- and refraction-matched, randomly recruited normal control group. In total, 312 eyes of 312 patients were included in this study, with 162 eyes in the RVO and 150 eyes in the control group. A significantly higher subfoveal choroidal thickness (SFCT) was found in the RVO (310.3 ± 72.5 (94 to 583) µm) as compared to the control group (237.0 ± 99.0 (62 to 498); p