Metabolic score for insulin resistance is associated with myopia in adolescents: A cross-sectional study with a complementary independent cohort

BACKGROUND: Adolescent myopia has risen sharply, yet the role of metabolic dysregulation remains unclear. This cross-sectional study investigated the association between the Metabolic Score for Insulin Resistance (METS-IR) and myopia in adolescents, and tested whether the interaction with obesity reflects biological synergy. METHODS: Cross-sectional analysis of 3946 adolescents aged 12-19 years from NHANES with complementary analysis in an independent clinical cohort of 561 East Chinese adolescents. Myopia was defined as spherical equivalent ≤ -0.5 diopters. Multivariable logistic regression, subgroup analyses, restricted cubic spline analyses, and sensitivity analyses were performed to assess the association, identify effect modifiers, characterize dose-response relationships, and evaluate the interaction. RESULTS: In NHANES, myopic adolescents had significantly higher METS-IR levels than non-myopes (32.1 vs. 31.3, P = 0.024). After full adjustment, high METS-IR (>31.84) was associated with 17% greater odds of myopia (OR = 1.17, 95% CI: 1.03-1.34), with a linear dose-response relationship and a myopia-specific exploratory reference point of 31.67. The association was significantly stronger in adolescents with obesity (P for interaction = 0.039). Sensitivity analyses using individual METS-IR components and the BMI-independent triglyceride-glucose index confirmed that the amplification of risk by obesity represents a statistical interaction consistent with biological synergy. In the independent cohort, the association remained significant after adjusting for parental myopia (OR = 1.13, 95% CI: 1.02-1.26). CONCLUSION: Higher METS-IR is independently associated with increased myopia risk in adolescents, particularly in those with obesity, and highlights METS-IR as a practical metabolic marker for risk stratification that may help guide nutritional and lifestyle interventions.