PURPOSE: The pathology of branch retinal vein occlusion (BRVO), a retinal circulatory disease, is related to monocular metamorphopsia-related vision impairment of the affected eyes, but the association of binocular metamorphopsia in such patients is unclear. This study aimed to examine the frequency of binocular metamorphopsia and its association with the clinical characteristics of patients with BRVO. METHODS: A total of 87 patients who were treated for BRVO-associated macular edema (ME) were included in this study. At baseline and 1 and 3 months after the initiation of anti-vascular endothelial growth factor (VEGF) treatment, we quantified metamorphopsia in the affected eyes and binocular metamorphopsia using the M-CHARTS diagnostic tool. RESULTS: At baseline, 53 and 7 patients had metamorphopsia in the affected eyes and binocular metamorphopsia, respectively. Although the visual acuity improved significantly after the initiation of anti-VEGF treatment, the mean M-CHARTS score in the affected eyes did not change from the baseline score. At 3 months, 9 patients showed binocular metamorphopsia; it was significantly associated with metamorphopsia in the affected eyes with a 95% confidence interval of 0.021-0.122 (β = 0.306, p = 0.006). CONCLUSION: Metamorphopsia in the affected eyes can cause binocular metamorphopsia in patients with BRVO-ME.