PurposeSagging eye syndrome (SES), esotropia with high myopia including heavy eye syndrome, and age-related esotropia (ARE)—collectively termed orbital pulley degeneration syndrome (OPDS)—are characterized by strabismus with orbital pulley lateral rectus-superior rectus band impairment. Herein, we examined body mass index (BMI) in OPDS to determine SES-associated anthropometric characteristics. DesignRetrospective cohort study. MethodsWe compiled and analyzed the BMI of patients aged ≥50 years who underwent strabismus surgery at a single center in Shizuoka, Japan, between July 2020 and March 2023. BMI (kg/m2) was categorized into four groups: <18.5, 18.5–21.9, 22–24.9, and ≥25. As the boundary between OPDS and SES is ambiguous, we assumed a pure SES group by excluding patients with ARE and esotropia with high myopia from the OPDS group. Overall, 204 patients (age: 67.7±9.7 years) were included in the study. ResultsThere were 78/126 and 49/119 patients in the OPDS/non-OPDS and SES/non-SES groups (age: 70.4±9.5/66.0±9.6 years, p=0.002 and 75.0±6.0/66.6±9.5 years, p<0.001; BMI: 21.2±3.3/23.2±3.0 kg/m2, p<0.001 and 21.2±3.3/23.1±3.0 kg/m2, p=0.003), respectively. In the BMI-stratified analysis, OPDS and SES were more prevalent in the <18.5 BMI group than in the 22–24.9 and ≥25 BMI groups (p<0.001 and p=0.006, respectively). Logistic regression analysis, adjusted for age and sex, showed that lower BMI was associated with a higher prevalence of OPDS and SES. ConclusionsPatients with OPDS, including SES, had lower BMI than other patients with strabismus. Therefore, BMI may be a clinical clue to SES.