Pain-induced effects on the pupillary light response under high and low illumination conditions.

Objective: The present study investigated the impact of two different light intensities on the pain-modulated pupillary light response (PLR). Additionally, it aimed to demonstrate parasympathetic and sympathetic influences on PLR parameters in response to pain, as predicted by functional models.

Method: A total of 24 participants were included in a randomized, repeated-measures design.