pupilgroottes

Pupilgroottes, a Dutch term for pupil size, refers to the size of the pupil, the opening in the center of the iris that regulates how much light enters the eye. The diameter is dynamically controlled to optimize vision under varying light and focusing tasks.

In humans and many animals, two iris muscles control diameter: the sphincter pupillae constricts the pupil in bright light, the dilator pupillae widens it in dim light.

Light conditions largely determine size: bright light typically yields smaller diameters (about 2-4 mm in humans) and dim light yields larger diameters (roughly 4-8 mm). Resting sizes vary among individuals and with age.

Other factors influence pupil size, including autonomic tone, circadian rhythm, medications (for example, mydriatics such as tropicamide widen the pupil; pilocarpine narrows it), trauma, and disease. Pupil asymmetry (anisocoria) can be physiologic or indicate pathology.

Measurement and clinical relevance: Pupillometry uses rulers, calipers, or specialized infrared cameras to quantify diameter and pupil reactivity. Clinically, the light reflex (pupil constriction in response to light) and the accommodation reflex are assessed to evaluate visual and neural function.

Clinical relevance and aging: Age-related changes include a typical reduction in baseline diameter (senile miosis). Abnormal latency or sluggish dilation can indicate nerve or muscle problems, such as third nerve palsy, Horner’s syndrome, or Adie’s pupil.

Across species, pupil size and shape vary widely. Some animals have round pupils; others have vertical or horizontal slits that adjust differently to light and gaze.