The Post-Illumination Pupil Response (PIPR)

All current PIPR metrics provide a direct measure of the intrinsic melanopsin photoresponse. To measure progressive changes in melanopsin function in disease, we recommend that the PIPR be measured using short-duration pulses (e.g., ≤ 1 second) with high melanopsin excitation and analyzed with plateau and/or 6-second metrics. Our PIPR duration data provide a baseline for the selection of interstimulus intervals between consecutive pupil testing sequences.