Association between myopia severity and pupillary dynamics: a quantitative smartphone-based pupillometry study

Quantitative assessment of pupillary dynamics provides an objective measure of autonomic and retinal function, with potential utility in the clinical evaluation of ocular and neurological conditions.

Increasing myopia severity may alter pupillary mechanisms, and smartphone-based pupillometry provides a non-invasive method to quantify these changes. The purpose of this study was to investigate alterations in static and dynamic pupillary parameters among emmetropes, low, moderate, and high myopia groups using smartphone-based pupillometry.

This comparative study included 160 participants (40 per group) aged 18-35 years. Pupillary dynamics were recorded with the Reflex Pro application under standardised illumination. Parameters analysed were latency, constriction velocity, maximum constriction speed, constriction amplitude, release amplitude, constriction time, and average pupil diameter. Intergroup differences were assessed using one-way ANOVA followed by Tukey's post hoc analysis, with p < 0.05 considered statistically significant.

Latency was significantly prolonged with increasing severity of myopia, ranging from 0.25 ± 0.05 s in emmetropes to 0.36 ± 0.08 s in high myopes (p < 0.001). Constriction velocity and maximum constriction speed showed progressive reduction, with high myopes exhibiting the slowest dynamics (2.9 ± 0.3 mm/s and 3.1 ± 0.3 mm/s, respectively; p < 0.001). Constriction amplitude and release amplitude also declined significantly across groups (p < 0.001). Constriction time was prolonged in high myopes (0.74 ± 0.09 s) compared to emmetropes (0.65 ± 0.08 s, p = 0.01). Average pupil diameter showed a trend towards increase in high myopes (5.8 ± 0.6 mm) but did not reach overall statistical significance (p = 0.06). Post hoc analysis confirmed that differences between emmetropes and high myopes were consistently significant for most parameters (p < 0.001).

Pupillary dynamics vary with myopia severity, with smartphone-based pupillometry offering a potential non-invasive assessment tool, though causality requires longitudinal validation.