Physiologic Anisocoria: A Manifestation of a Physiologic Sympathetic Asymmetry

Abstract

Forty-two consecutive subjects identified clinically by other clinicians as having anisocoria were evaluated by the author in a blinded fashion with the friction sweat test. The presence and side of any ptosis or lid fissure narrowing was also noted. Thirty-three of 42 (79%) had an associated decrease in sweating on the same side as the smaller pupil. Three (7%) had decreased sweating contralateral to the miosis and in 6 (14%) no significant asymmetry could be detected. Fifteen had an associated ptosis and narrowed lid fissure, all but one ipsilateral to the miosis. These findings strongly suggest that physiologic anisocoria is a manifestation of a physiologic asymmetry of resting sympathetic tone.

KEYWORDS:

• anisocoria
• miosis
• ptosis
• sweating
• Horner's