Encyclopedia > Iris of the eye

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Iris (anatomy)

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Iris, in anatomy, is the sphincter around the pupil of the eye, permitting the pupil to open and close to control the amount of light striking the retina. The iris is brightly pigmented, with colours ranging from grey to green, blue, brown, and nearly purple or black.

A person's "eye colour" is actually the colour of their iris (except, of course, that a black eye is a bruise[?] of the skin around the eye, and pink eye is a kind of infection). Certain eye colours are sometimes seen as being especially attractive, and cosmetic contact lenses can be worn to mask one's natural eye colour with another.

When photographed with a flash, the iris cannot close fast enough, resulting in the red eye effect.

Scanning the iris is a biometric[?] method used for the recognition of human individuals.

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