The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. [1] It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within …

The pupil is the black hole in the center of the colored part of your eye (iris). The pupil is the pathway that lets light get to your retina.

The meaning of PUPIL is a child or young person in school or in the charge of a tutor or instructor : student.

2019年2月26日 · Adie's tonic pupil. This is a pupil that has nearly no reaction to light (direct or consensual) and there is a delayed reaction to accommodation. Adie's tonic pupil (also called Adie's pupil, tonic pupil, or Adie's syndrome) usually affects only one eye, with the affected pupil being larger than the pupil of the unaffected eye. The cause of ...

PUPIL definition: 1. a person, especially a child at school, who is being taught: 2. someone who is being taught a…. Learn more.

2025年3月25日 · A pupil is the opening created by the iris, which widens and narrows to control the amount of light that enters the eye. Pupil size can vary between people, but they should be round, equal in size, and contract or dilate at the same time.

Pupil, in the anatomy of the eye, the black centre opening within the iris through which light passes before reaching the lens and being focused onto the retina. The size of the opening is governed by the muscles of the iris, the coloured part of …

2023年10月30日 · 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 pupil’s function is to allow light to pass through and enter the eye.

2025年2月10日 · 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 room is lighted, there is an immediate constriction of the pupils, the light reflex.

2025年1月22日 · The pupil is the black, circular opening in the center of the eye that allows light to enter and reach the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye.