To determine the incidence of idiopathic epiretinal membrane (ERM) and its risk factors in Korean adults.

A total of 16,495 participants (≥50 years of age) who had at least two examinations from January 2006 to December 2016 were included in this study. The incidence of idiopathic ERM was determined and age-standardized to the 2010 Korean Census.

Idiopathic ERM developed in 391 of 15,399 participants who had no previous ERM in either eye at the baseline examination. The overall age-standardized incidence was 2.18% (95% confidence interval [CI], 1.89–2.38), including 1.39% with cellophane macular reflex and 0.79% with preretinal macular fibrosis. Multivariate Cox regression analyses revealed that the factor related to the development of idiopathic ERM was obesity (body mass index >25 kg/m²; adjusted hazard ratio, 0.77; 95% CI, 0.60–0.97) after adjusting for confounding factors.

The incidence of idiopathic ERM in Korean adults was lower than that of other ethnic studies. Further studies are needed to confirm the inverse relationship between obesity and the incidence of ERM in this population.