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Variant of miosis.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
myosiscontraction of the pupil of the EYE.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
Contraction of the pupil or condition in which the pupil is very small (2 mm or less in diameter). It can be brought about by a spasm of the sphincter muscle or by the effect of a miotic drug (e.g. eserine, neostigmine, pilocarpine), or in certain spinal diseases or any stimulation of the parasympathetic supply to the eye. Miosis occurs naturally when doing close work or when stimulated by light. Note: also spelt myosis. See corneal reflex; pupil light reflex; baring of the blind spot; Horner's syndrome.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann