The pupil's response after light exposure is reduced in seasonal depression

Individuals with seasonal affective disorder (SAD) demonstrated a reduced post illumination pupil response (PIPR) to blue light compared to healthy controls.

• SAD participants showed a lower PIPR and percent change in PIPR when exposed to blue light stimuli.
• The PIPR response varied based on the OPN4 I394T genotype, indicating a potential genetic influence on light sensitivity.
• No variation in PIPR was linked to the OPN4 P10L genotype.
• These findings suggest that SAD may be associated with decreased sensitivity in the light input pathway, affecting neurobiological and behavioral responses.

Simplified