Associations between quadrant retinal layer thickness and pupillary light reflex in axial myopia

To evaluate the impact of various factors, including sex, retinal thickness, and axial length (AL), on pupillary light reflex (PLR) in young individuals with axial myopia.

Sixty-two patients (50% male) were recruited for this study. AL and anterior chamber metrics were measured. Ocular fundus images for quadrant retinal layer segmentation were obtained automatically using swept-source optical coherence tomography. PLR metrics, including constriction and dilation metrics (ratio, time, and velocity), were derived using the pupillometry technique.

Male participants showed a weaker peak pupillary constriction ratio compared with females (32.99 ± 4.85% versus 36.15 ± 5.21%, P = 0.0143). The constriction period metrics (peak ratio, time, mean velocity, and maximum velocity) showed no correlation with the AL. The maximum constriction velocity was positively affected by the ganglion cell-inner plexiform layers (GCIPL) and the entire retinal thickness in most outer annular regions (all P < 0.05). In male participants only, the peak pupil constriction ratio was affected by similar outer annular regions in the GCIPL and entire retinal thickness (all P < 0.05). The accelerated pupillary dilation time were affected by both higher AL (β=-0.256 s/mm, P = 0.038) and thicker macular retinal nerve fiber layer (mRNFL) thickness, especially in inner nasal, and outer nasal region (both P < 0.05).

Axial elongation exerts no significant impact on the constriction procedure but accelerates post-illumination dilation. Reduced outer annular GCIPL thickness is associated with attenuated pupillary constriction velocity, whereas thinning of the mRNFL in the nasal direction correlates with prolonged dilation latency.