Changes in Ocular Biomechanics During Adolescence and Its Relationship with Lifestyle and Myopic Progression: The Oporto Myopia Study

The relationship between lifestyle, ocular biomechanical behavior, and myopia is not well established in the literature. The present study aims to describe changes in ocular biomechanics during adolescence and to explore their relationship with lifestyle factors and myopic progression. Prospective cohort study including 63 adolescents (126 eyes) with a mean age of 14.1 ± 2.6 years old examined twice over a 30 ± 0.9-month period. The data from biomechanics, biometry, corneal tomography, and lifestyle was addressed. The relationships between biomechanical changes, biometric and refractive variation, and lifestyle variables were analyzed using parametric and non-parametric statistics with a significance level of <i>p</i> < 0.05. A biomechanical stiffening trend was found. Axial elongation was 0.12 ± 0.17 mm, and refractive shift was -0.32 ± 0.87 D. The history of allergies was associated with greater axial growth (<i>p</i> = 0.032) and smaller increase in stress-strain-index (SSI) (<i>p</i> = 0.01). Myopization was higher in eyes with ocular surface symptoms (<i>p</i> = 0.049) and those with reported eye-rubbing habits (<i>p</i> = 0.04), with a lower gain in stiffness (<i>p</i> < 0.05). Outdoor activities were associated with higher gain in corneo-scleral stiffness (<i>p</i> < 0.05). Reduced myopization correlated directly with the increase in the SSI (<i>p</i> < 0.05) and inversely with the Integrated Radius (<i>p</i> < 0.05). Greater increases in axial length (AL), vitreous cavity length (VCL), and the ratio between VCL and AL (R_VCL/AL) correlated negatively with the increase in the SSI (<i>p</i> < 0.05). The increase in the R_VCL/AL correlated positively with the time spent on digital devices and negatively with the amount of outdoor activity (<i>p</i> < 0.05). Biomechanics may represent the physiological bridge between the environmental exposure and myopization, as lower gain in corneo-scleral stiffness was consistently associated with greater axial elongation and refractive myopization, with outdoor activity appearing to be protective.