Abstract Background To evaluate the prevalence of blepharoptosis among Korean adults and the characteristics of blepharoptosis patients, and to determine an appropriate age threshold for recommending blepharoptosis evaluation. Methods The Korean National Health and Nutrition Examination Survey (KNHANES-V) was conducted in 2010–2012. We extracted data on 17,878 Korean adults aged more than and equal to 19 years included in KNHANES-V, and determined blepharoptosis prevalence according to age, to determine the cutoff age for recommending blepharoptosis evaluation. We also determined the possible association between blepharoptosis and obesity parameters, such as body mass index (BMI) and waist circumference (WC). Results There was astrong association between older age and the prevalence of blepharoptosis. The cutoff age for recommending blepharoptosis evaluation was 63 years for males, 70 years for females, and 66 years for all patients. Patients with a high BMI and large WC had a higher prevalence of blepharoptosis in all age groups except for those aged over 80 years. The association of blepharoptosis with BMI according to age group showed that in the 50–59 and 60–69 years age groups, blepharoptosis prevalence and BMI were higher. However, in the 70–79 and 80–89 years age groups, extremely obese patients (BMI > 30) showed a decreased blepharoptosis prevalence. Conclusions Moderate to severe blepharoptosis can result in poor visual function and exacerbate headaches and depression, leading to decreased quality of life. This study proposed an appropriate age threshold for recommending evaluation of patients with blepharoptosis among the general population of Korea.