reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller
(genetics) cell division that produces reproductive cells in sexually reproducing organisms; the nucleus divides into four nuclei each containing half the chromosome number (leading to gametes in animals and spores in plants)
Condition in which the pupil is constricted Occurs as a normal response to a bright light stimulus, to focusing on a near object (known as accommodation), or to administer certain drugs See Free Eye Tests