mydriasis

from WordNet (r) 3.0 (2006)

mydriasis
    n 1: reflex pupillary dilation as a muscle pulls the iris
         outward; occurs in response to a decrease in light or
         certain drugs

from The Collaborative International Dictionary of English v.0.48

Mydriasis \My*dri"a*sis\, n. [L., fr. Gr. ?.] (Physiol. & Med.)
   A long-continued or excessive dilatation of the pupil of the
   eye.
   [1913 Webster]

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