Describing Anisocoria in Neurocritically Ill Patients.

BACKGROUND: Anisocoria (unequal pupil size) has been defined using cut points ranging from greater than 0.3 mm to greater than 2.0 mm for absolute difference in pupil size. This study explored different pupil diameter cut points for assessing anisocoria as measured by quantitative pupillometry before and after light stimulus. METHODS: An exploratory descriptive study of international registry data was performed. The first observations in patients with paired left and right quantitative pupillometry measurements were included. Measurements of pupil size before and after stimulus with a fixed light source were used to calculate anisocoria. RESULTS: The sample included 5769 patients (mean [SD] age, 57.5 [17.6] years; female sex, 2558 patients [51.5%]; White race, 3669 patients [75.5%]). Anisocoria defined as pupil size difference of greater than 0.5 mm was present in 1624 patients (28.2%) before light stimulus; 645 of these patients (39.7%) also had anisocoria after light stimulus (P < .001). Anisocoria defined as pupil size difference of greater than 2.0 mm was present in 79 patients (1.4%) before light stimulus; 42 of these patients (53.2%) also had anisocoria after light stimulus (P < .001). DISCUSSION: The finding of anisocoria significantly differed before and after light stimulus and according to the cut point used. At most cut points, fewer than half of the patients who had anisocoria before light stimulus also had anisocoria after light stimulus. CONCLUSION: The profound difference in the number of patients adjudicated as having anisocoria using different cut points reinforces the need to develop a universal definition for anisocoria.

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.

Interrater Reliability of Pupillary Assessments.

BACKGROUND: Subjective scoring of pupil reactivity is a fundamental element of the neurological examination for which the pupillometer provides an objective measure. METHODS: This single-blinded observational study examined interrater reliability of pupil exam findings between two practitioners and between practitioners and a pupillometer. RESULTS: From 2329 paired assessments, the interrater reliability between practitioners was only moderate for pupil size (k = 0.54), shape (k = 0.62), and reactivity (k = 0.40). Only 33.3% of pupils scored as non-reactive by practitioners were scored as non-reactive by pupillometry. CONCLUSIONS: Despite the strong emphasis placed on the traditional pupil examination, especially for patients with a neurological illness, there is limited interrater reliability for subjective scoring of pupillary assessments. Thus, the use of automated pupillometers should be examined as a potential method to increase the reliability of measuring of pupil reactivity.