Table 1 Definitions for the PLR metrics during light stimulation and PIPR metrics after light offset (following Adhikari et al., 20157).

From: Effect of Age and Refractive Error on the Melanopsin Mediated Post-Illumination Pupil Response (PIPR)

Metrics

Definition and Units

Baseline pupil diameter (BPD)

Average 5 s pre-stimulus period (mm, %)

PLR Metrics

Transient PLR

Peak % change from 180–500 ms after light onset11,34

Peak pupil constriction

Minimum pupil size (% baseline) during light presentation

PIPR Metrics

6 s PIPR amplitude

Pupil size (% baseline) at 6 s after light offset8,32,49

Plateau PIPR

Plateau of exponential model (% baseline)8

AUC early

∑ (BPD - APD)* over 0–10 s after light offset (unitless)50

AUC late

∑ (BPD - APD) over 10–30 s after light offset (unitless)50

  1. *APD = absolute pupil diameter.
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