Anisocoria After Direct Light Stimulus is Associated with Poor Outcomes Following Acute Brain Injury

Area of Science:

• Neuroscience
• Ophthalmology
• Critical Care Medicine

Background:

• Pupil size and reactivity assessment is standard for neurocritically ill patients.
• Anisocoria (unequal pupil size) in these patients often necessitates further investigation and treatment.
• This study investigates anisocoria as a predictor of discharge modified Rankin Scale (mRS) scores.

Purpose of the Study:

• To explore anisocoria at rest and after light stimulus using quantitative pupillometry.
• To determine if anisocoria predicts discharge modified Rankin Scale (mRS) scores in neurocritically ill patients.
• To compare the prognostic value of anisocoria at rest versus after light stimulus.

Main Methods:

• Analysis of an international registry including patients with paired pupillometry and discharge mRS scores.
• Anisocoria defined by pupil size difference (>0.5 mm, >1 mm, >2 mm).
• Nonparametric models used to assess outcome predictors: anisocoria at rest, after light stimulus, and persistent anisocoria.

Main Results:

• 152,905 observations from 6,654 patients analyzed.
• Anisocoria after light stimulus (using >0.5 mm cutoff) was associated with worse median mRS scores (2) than anisocoria at rest (1).
• Persistent anisocoria showed significantly worse outcomes (median mRS 3) compared to no persistent anisocoria (median mRS 1).

Conclusions:

• Anisocoria after light stimulus is a novel biomarker indicating a worse prognosis than anisocoria at rest.
• Anisocoria after light should be considered for routine clinical assessment and trending in neurocritical care.
• Further validation is recommended for incorporating this biomarker into clinical practice.