Horner's pupil

Hor·ner's pupil

A pupil that is constricted due to impairment of the sympathetic nerve of the dilator muscle of the pupil.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
References in periodicals archive ?
A set of case studies in neuromotility disorders is included along with appendices covering optic nerve diseases, covert retinal disease, optic disc anomalies, gaze paresis, saccadic intrusions and bobbing, Horner's pupil, episodic papillary mydriasis, and the pupil in coma.
Cocaine is a noradrenaline re-uptake inhibitor that results in increased noradrenaline levels at the neuromuscular junction of the normal pupil; hence mydriasis occurs in the normal pupil but not in the noradrenaline-deficient Horner's pupil. Topical cocaine is a weak dilator of the normal pupil, with many documented failures.
(5) The presynaptic [[alpha].sub.2]-activity, which inhibits the release of noradrenaline, is negligible in the presence of noradrenaline deficiency in the Horner's pupil. (5) The effect of apraclonidine is most evident 30 minutes after instillation when the result should be interpreted.