Which term describes pupillary constriction?

The term that describes pupillary constriction is miosis. Miosis refers to the constriction of the pupils, often occurring in response to bright light or as part of a reflex mediated by the parasympathetic nervous system. This process serves to reduce the amount of light entering the eye, protecting the retina and improving visual acuity in bright environments.

The other terms listed have distinct meanings that do not pertain to pupillary constriction. Mydriasis refers to the dilation of the pupils, which is the opposite of miosis. Anisocoria indicates a condition where the pupils are of unequal sizes, and refraction is a term related to the bending of light as it passes through different media, which is not specific to any changes in pupil size. Understanding these terms is important for recognizing different physiological states and conditions related to vision and eye function.