To analyze the pathophysiology of epiretinal membrane foveoschisis (ERM-FS) by evaluating the longitudinal changes in visual function and several optical coherence tomography (OCT) parameters. The medical records of 33 consecutive patients (35 eyes) with untreated ERM-FS were retrospectively reviewed. Best-corrected visual acuity (BCVA), M-CHARTS score, and OCT parameters including ERM area, maximum depth of retinal folds (MDRF), FS area, and FS circularity were evaluated. A wide range of FS area changes was observed at the final follow-up visit (59.68-240.45% of the baseline FS area). In the FS enlargement group, BCVA and mean M-CHARTS scores significantly worsened and MDRF significantly increased over time, whereas in the FS non-enlargement group, no significant change was observed in BCVA, mean M-CHARTS scores, or MDRF during the follow-up period. Multivariate logistic regression analyses revealed that MDRF (odds ratio: 1.05, 95% confidence interval: 1.00-1.10, P = 0.048) and FS circularity (odds ratio: 0.91, 95% confidence interval: 0.83-1.00, P = 0.043) were significantly associated with FS enlargement. ERM-FS encompasses diverse pathophysiologies. Since visual functions do not worsen in some cases, monitoring the changes in visual functions and retinal morphology over time is recommended to determine surgical indications.