Fig. 2From: Melanopsin-mediated pupillary responses in bipolar disorder—a cross-sectional pupillometric investigationThe post-illumination pupillary response to blue light (PIPR) as a function of illness duration (years since initial depression/mania/hypomania. A higher value indicates a greater post-illumination contraction relative to baseline. The linear regression model predicts a 7% increase in the post-illumination pupillary response to blue light for every 10-year increase in disease duration, p = 0.02Back to article page