n. 瞳孔放大

[医] 瞳孔开大, 瞳孔散大, 瞳孔扩大

[ noun ]
reflex pupillary dilation as a muscle pulls the iris outward; occurs in response to a decrease in light or certain drugs
<noun.act>

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