Clinical factors affecting pupillary light reflex parameters: a single-centre, cross-sectional study

Area of Science:

• Ophthalmology
• Physiology
• Biostatistics

Background:

• The pupillary light reflex (PLR) is a crucial indicator of autonomic nervous system function.
• Understanding factors influencing PLR is essential for its clinical application as a diagnostic tool.

Purpose of the Study:

• To investigate the impact of stimulus intensity, aging, sex, smoking, and eye symmetry on pupillary light reflex (PLR) parameters.
• To compare the performance of standard linear regression models versus linear mixed-effects models (LMMs) in analyzing PLR data.

Main Methods:

• A cross-sectional study involving 2812 eyes from 1406 subjects.
• PLR data were collected using four distinct stimulus intensities.
• Two modeling approaches were employed: standard linear regression (Model A) and LMMs accounting for among-individual variability (Model B).
• Model fit was assessed using Akaike's Information Criterion (AIC).

Main Results:

• Linear mixed-effects models (LMMs) demonstrated a superior fit across all PLR parameters.
• Stimulus intensity, age, and eye symmetry showed consistent effects across both models.
• Sex and smoking index revealed divergent results between Model A and Model B, with LMMs indicating non-significance where standard regression suggested significance.

Conclusions:

• Light stimulus intensity, aging, sex, smoking, and eye symmetry are significant modulators of PLR parameters.
• Incorporating LMMs to adjust for among-individual variability enhances model fit and reduces false positives.
• Accurate assessment of clinical factors influencing PLR is crucial for its diagnostic utility.