Pupilar

Pupilar is an adjective used to describe anything related to the pupil of the eye, the circular opening in the iris that regulates the amount of light reaching the retina. In contemporary English medical literature, the more common form is pupillary, while pupilar is found in some languages and older texts.

The pupil’s size is controlled by two smooth muscles: the sphincter pupillae, which constricts the pupil (miosis) in bright light or near focus, and the dilator pupillae, which enlarges the pupil (mydriasis) in dim light or under sympathetic stimulation. The sphincter receives parasympathetic input mainly via the oculomotor nerve (CN III), while the dilator is driven by sympathetic pathways from the hypothalamus to the superior cervical ganglion.

Pupillary responses are part of the pupillary light reflex. When light hits the retina, signals travel to the pretectal area and then to the Edinger–Westphal nucleus, triggering constriction of the pupil in both eyes (direct and consensual responses). Pupillary size can be measured over time with pupillometry, a tool used in neurology and anesthesia.

Abnormal pupilar findings may indicate ocular or neurological conditions. Anisocoria refers to unequal pupils and can be harmless or clinically significant. A dilated, poorly reactive pupil may reflect third-nerve palsy, pharmacologic mydriasis, or trauma, while a small or slow-to-dilate pupil can occur in Adie’s tonic pupil or Horner’s syndrome. Drugs that affect the autonomic nervous system can alter pupilar size and reactivity.

In summary, pupilar describes attributes, reflexes, and conditions related to the pupil, a critical element of vision and neurological assessment.