Comparison of visual functions among early and late onset myopia.

Early-onset myopia (EOM) progresses more rapidly and sets a higher risk of developing high myopia, whereas late-onset myopia (LOM) is typically associated with lower refractive error. However, differences in visual function between these groups remain underexplored. This cross-sectional study compared high-contrast visual acuity, low-contrast visual acuity, contrast sensitivity function (CSF), blur perception, and depth of focus in individuals with EOM and LOM. Twenty participants (10 EOM, 10 LOM) aged 18-35 years with myopia ranging from - 0.50 to - 6.00 D were included. Visual function assessments were conducted using MATLAB and PsychoPy software, with all measurements taken under full-distance spectacle correction. While high-contrast and low-contrast visual acuity showed no significant differences, CSF parameters showed significant differences. The area under the curve, peak spatial frequency, and cutoff spatial frequency were significantly lower in EOM than in LOM (p = 0.019, 0.032, and 0.005, respectively). Blur perception thresholds also varied, though statistical significance was not reached. These findings suggest that individuals with EOM may show compromised contrast sensitivity, possibly affecting their overall visual quality. Understanding these functional differences can help in developing targeted interventions for myopia management, ensuring personalized approaches to optimize visual performance across different onset groups.