Figure 2.

The post-illumination pupil response (PIPR) and the maximum pupil constriction to monocular blue and red light stimuli in healthy controls and patients with idiopathic intracranial hypertension (IIH). The blue and red colours indicate the stimulus colour, and the dark traces indicate the mean of PIPR and maximal pupil constriction. The PIPR and maximal pupil contraction are expressed relative to pupil size prior to light onset, i.e., a smaller value on the y-axis corresponds to pupil constriction relative to pupil size before light onset.