mi·o·sis also my·o·sis 
(mī-ōsĭs)
(mī-ōsĭs)n. pl. mi·o·ses (-sēz) also my·o·ses
Constriction of the pupil of the eye, resulting from a normal response to an increase in light or caused by certain drugs or pathological conditions.
[Greek mūein, to close the eyes + -OSIS.]