The iris (pl.: irides or irises) is a thin, annular structure in the eye in most mammals and birds that is responsible for controlling the diameter and size of the pupil, and thus the amount of light reaching the retina. In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm. Eye color is defined by the iris.

Jul 24, 2024 · The iris works with the rest of your eye to help you see. Specifically, it controls how much light enters your eye. Muscles in your iris adjust your pupil automatically based on changes in lighting.

Oct 31, 2024 · The iris regulates the light entering the eye by changing the size of the pupil based on the situation. For example, when it’s dark, the iris muscles expand the pupils to allow more light into the eye.

Oct 22, 2024 · The iris is the colored, muscular curtain of the eye. Located between the cornea and lens, the iris regulates how much light gets into the eye by dilating and constricting. Disorders that affect the iris can occur due to genetic abnormalities or other conditions.

Nov 4, 2024 · The iris helps control the amount of light that reaches the retina in the back of the eye. Muscles in the iris allow the pupil to dilate (widen) to let in more light and constrict (narrow) to let in less light.

Jan 14, 2021 · Iris and Pupil: Light passes through the cornea and aqueous humor through a hole called the pupil. The iris is a contractile ring that determines eye color and controls the size of the pupil. The iris dilates (opens) the pupil in low light so more light enters the eye and constricts in …

Feb 26, 2019 · Here are the key things you should know about the uvea of your eye. Iris and uvea definition. The uvea is the pigmented middle layer of the eyeball. It has three segments: the iris, the ciliary body and the choroid. Iris: The iris of the eye is the thin, circular structure made of connective tissue and muscle that surrounds the pupil. The color ...

After passing through the cornea, light travels through the pupil (the black dot in the middle of the eye). The iris—the circular, colored area of the eye that surrounds the pupil—controls the amount of light that enters the eye.

Iris: The iris is the colored part of the eye that surrounds the pupil. It regulates the amount of light that enters the eye. Lens: The lens is a clear part of the eye behind the iris that helps to focus light and images on the retina. Macula: The macula is the small, sensitive area of …

Jan 22, 2025 · The iris is a key structure in the eye responsible for controlling the size of the pupil and regulating the amount of light that enters the eye. Its unique anatomical features contribute to its ability to adjust to varying light conditions and its distinctive coloration.