9897 total pupil observations from 221 patients with intracranial injury. New Onset Anisocoria (NOA), defined as a new episode of pupil size difference >1mm (i.e., was not preceded by anisocoria in two prior measurements) occurred in 63% of patients, and in 5.4% of total pupil observations. NOA with abnormal pupil reactivity (NOA-Abnormal) is highlighted in purple and occurred at least once in 61 patients (27%), and in 174 observations (1.8% of all observations, 32.5% of NOA observations). NOA with normal pupil reactivity (NOA-Normal) occurred in 360 observations (3.6% of all observations). Of note, data points in which pupil size difference is >1 mm but not designated as NOA-Abnormal or NOA-Normal are anisocoric measurements immediately preceded by another episode of anisocoria and are therefore not new.