Inter-device reliability of the NPi-100 pupillometer

The purpose of this study was to explore the inter-device reliability of NPi-100 pupillometers (NeuroOptics, Inc.). The pupillary examination is a fundamental element of the neurological exam. Current evidence suggests that the traditional examination of the pupil with a hand held flashlight has limited inter-rater reliability. Automated pupillometers were developed to provide an objective scoring of pupil size and reactivity. However, there are no data examining inter-device reliability of automated pupil assessments. This study included 210 paired pupillometer measurements were obtained by 33 practitioners from 20 patients at risk for cerebral edema. There was no statistically significant difference between the mean maximum pupil size at rest, the minimum pupil size during light stimulation, and the mean pupil reactivity, for both the right and left eye, when assessed by two investigators, each with a different pupillometer. In addition, Cohen's Kappa assessments of pupil size and reactivity revealed an almost perfect agreement between the two pupillometers for the maximum pupil size, the minimum pupil size, and for pupil reactivity for both eyes. There is a high inter-device reliability of automated pupillary assessments by two practitioners examining the same patient using different NPi-100 pupillometers.