Prevalence and associated factors of blepharoptosis in Korean adult population: The Korea National Health and Nutrition Examination Survey 2008-2011

Purpose This study aimed to evaluate the prevalence and associated factors of involutional blepharoptosis in a nationwide representative sample in Korea. Methods Cross-sectional study 20 941 Korean men and women 40 years of age and older who participated in last 2 years (2008 and 2009) of the 4th wave of the Korean National Health and Nutrition Examination Survey (KNHANES) IV and the first 2 years (2010 and 2011) of KNHANES V. Ocular examinations were performed by ophthalmologists trained in procedure and grading methods, and blepharoptosis was defined as a marginal reflex distance o2mm on either eye. Results The prevalence of involutional blepharoptosis in the Korean adult was 13.5% (95% CI: 12.1%, 14.9%). It was increasing along with aging (5.4% among 40's and 32.8% in people over 70 years old). A statistically significant negative association between levator function and blepharoptosis was found. With right eye, while only 5.4% (95% CI: 4.5%, 6.2%) had blepharoptosis among people whose levator function was excellent (>= 12 mm), 71.4% (95% CI: 60.0%, 85.9%) of people whose levator function was poor (<= 4 mm) had blepharoptosis. Hypertension, diabetes, higher body mass index (BMI), and lower education had statistically significant association with blepharoptosis adjusting all other confounders. Conclusions The distribution and proportional changes of levator function and marginal reflex distance 1 (MRD1) with aging implicate a contributory role of muscular degeneration. Strong association with hypertension, diabetes, BMI, and education level suggests that etiology of involutional blepharoptosis would be multifactorial and further investigation would be necessary to determine precise mechanism and contribution of factors.