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The iris is a contractile structure, consisting mainly of smooth muscle, surrounding the pupil.Light enters the eye through the pupil, and the iris regulates the amount of light by controlling the size of the pupil. This is known as the pupillary light reflex.. The iris contains two groups of smooth muscles; a circular group called the sphincter pupillae, and a radial group called the dilator ...
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. Adie syndrome: This condition means that your pupil stays dilated and doesn't react normally to changes in light. It can also make your pupil stay constricted rather ...
Learn what's normal pupil size and how it can vary depending on light, distance, health, drugs, and emotions. Find out what causes pupils to dilate or constrict and when to see a doctor.
Uneven pupils can be caused by a brain aneurysm, blood vessels in the neck being torn or blocked, and as a reaction to certain topical dilating medication that only reaches one eye. However, people born with uneven pupils and experience no harmful symptoms shouldn't need to worry. This is known as physiologic anisocoria and isn't cause for concern.
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 light ...
Learn about the definition, function, size, testing and conditions of the pupil, the opening in the center of the iris that allows light to enter the eye. Find out how pupils respond to light, accommodation and sexual arousal, and what abnormal pupil responses mean.
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. This light then interacts with the cells of the retina, working as part of the visual pathway to provide the ability of sight.. The pupil changes size to allow more, or less, light to ...
The normal pupil size in adults varies from 2 to 4 mm in diameter in bright light to 4 to 8 mm in the dark. The pupils are generally equal in size. They constrict to direct illumination (direct response) and to illumination of the opposite eye (consensual response). The pupil dilates in the dark. Both pupils constrict when the eye is focused on a near object (accommodative response). The pupil ...
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 the eye. These muscles rapidly constrict the pupil when exposed to bright light and expand (dilate) the pupil in dim light.
Human eye - Pupil, Iris, Retina: 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. This is bilateral, so that even if only one eye is exposed to the light, both pupils ...