Associations of postural asymmetry with refractive error: an objective photogrammetric analysis in students

To assess associations between objectively measured postural misalignments and refractive errors in Chinese adolescents.

A school-based, cross-sectional study was conducted on 567 students aged 12-18 years. Participants underwent comprehensive eye examinations including cycloplegic autorefraction and axial length (AL) measurement and objective postural quantification using a photogrammetric system. Questionnaire-derived covariates for myopia risk factors were available for 258 participants. Multivariable logistic and linear regression models assessed associations between postural misalignments and refractive outcomes.

The study population (mean age: 14.96 ± 1.60 years; 43.4% male) exhibited a high prevalence of myopia (82.5%) and anisometropia (34.7%). In the primary multivariate analysis (n = 567), head tilt was a significant risk factor for anisometropia (OR = 1.71, p = 0.013) and correlated with larger inter-eye differences in SE and axial length. In the sensitivity analysis (n = 258), the association between head tilt and anisometropia remained significant (OR = 1.94, p = 0.049) after adjusting for parental myopia and lifestyle factors. Although shoulder imbalance was initially associated with SE (β = -0.48, p = 0.030) and AL (β = 0.24, p = 0.025), this association became non-significant after including parental myopia and lifestyle-related factors. Forward head posture showed no significant associations with refractive parameters.

Asymmetrical postural misalignments have distinct associations with refractive errors. Head tilt and poor writing posture exhibit distinct associations with anisometropia. These findings highlight the potential value of postural assessment in myopia management.