Interpupillary Distance and Peripapillary Myopic Changes: A Pilot Study

Myopia is associated with structural changes of the optic nerve head (ONH), such as optic disc ovalization and gamma peripapillary atrophy (γPPA). Recent biomechanical theories suggest that optic nerve sheaths (ONS) traction during adduction may contribute to these changes. Based on geometric considerations, interpupillary distance (IPD) may influence adduction amplitude, and we investigated whether IPD is associated with ONH features, namely the ovality index (OI) and γPPA width. In this monocentric cross-sectional study, 100 eyes from 100 adults (mean age 62.6 ± 13.7 years) were analyzed. Axial length (AL), refractive error, and IPD were recorded. OI and γPPA width were assessed using spectral-domain OCT. Pearson correlations and multivariable linear regressions were performed, adjusting for age, gender, and myopia status. IPD showed no significant correlation with OI (r = 0.001; p = 0.989) or γPPA (r = −0.028; p = 0.789). In adjusted models, IPD was not associated with either OI or γPPA. IPD showed a weak correlation with AL, but this was not significant (p = 0.059). AL was strongly associated with both lower OI and wider γPPA (p < 0.001). IPD-related biomechanical forces do not appear to influence ONH shape or γPPA. Axial elongation remains the key driver of myopic ONH remodeling.