pupillae

Pupillae is the plural form of pupilla, a Latin term historically used to denote the pupil of the eye. In contemporary English, the everyday term is pupil, and pupillae appears mainly in historical, anatomical, or Latin-labeled contexts.

The pupil is the opening in the center of the iris that regulates the amount of light reaching the retina. Its size is controlled by two sets of smooth muscle in the iris: the sphincter pupillae, which constricts the pupil, and the dilator pupillae, which enlarges it. Parasympathetic innervation via the oculomotor nerve induces constriction, while sympathetic pathways drive dilation. The balance between these actions allows the pupil to adapt to varying lighting conditions and to participate in depth of field and focus.

Pupillary size and reactivity are commonly assessed in clinical practice through the pupillary light reflex, which involves afferent pathways from the retina and efferent pathways to the iris muscles. Normal variation occurs with age and lighting; pharmacologic agents, neurological or ocular disease can alter size, shape, or reactivity. Conditions such as anisocoria describe unequal pupils, while mydriasis refers to dilation and miosis to constriction.

In modern usage, pupillae is largely of historical or Latin-labeled relevance, with the standard term in everyday language being the pupil. The term may be encountered in older anatomical texts, nomenclature, or descriptive labels, and its meaning aligns with the same anatomical structure known as the pupil.