In optical terms, the anatomical pupil is the eye's aperture and the iris is the aperture stop. The image of the pupil as seen from outside the eye is the entrance pupil, which does not exactly correspond to …

Oct 4, 2022 · Small pupils can happen when you’ve had a stroke or when you’ve used opiates, among other reasons. Mydriasis is the name of the opposite condition, having dilated pupils.

Mar 21, 2026 · The amount of light entering the eye is restricted by the aperture in the iris, the pupil. In a dark room, a person’s pupils are large, perhaps 8 mm (0.3 inch) or more in diameter. When the …

Dec 4, 2024 · Pupils are the dark-colored openings at the center of your eyes that let light in. Doctors can look at your pupils for clues about your health. The size of your pupils and how they react to...

Jan 6, 2026 · A pupil is the opening created by the iris, which controls the amount of light that enters the eye. Learn about medical conditions affecting the pupils.

Why should I learn about the eye? If you know the parts of the eye, you will better understand how the eye works and how diseases and conditions can affect your vision.

Apr 10, 2026 · Light rays enter the eye through the clear cornea, pupil, and lens.

Oct 30, 2023 · Structure of the eyeball seen in a transverse section. The pupil is the small black circle located in the center of the eyeball. Surrounding the pupil is the colored part of the eye, the iris. The …

The comprehensive definition of pupil. Includes pronunciation, synonyms, etymology, and usage examples to help you master this word.

: the usually round opening in the iris that contracts and expands to control the amount of light entering the eye.