What Is The Function Of Iris

Iris Eye Definition The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina.

The Iris is the most anterior part of the uvea. It is a thin, contractile and circular disc, with the pupil centrally perforated.

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The anterior section of the uvea forms the bulk for the body of the iris, and as a result, the inflammation of the iris is known as anterior uveitis or iritis. The posterior section of the uvea is known as choroid.

Iris is a genus of flowering plants with showy flowers in the family Iridaceae.

The Iris is a thin, pigmented structure found in the eye that can regulate the amount of light that can enter the retina. Additionally, it is responsible for determining the eye colour.

Iris

The Iris is located in the front portion of the eye’s lens. It is the visible part of the eye and is pigmented and opaque. The Iris’ muscles control the size of the pupil, which is the aperture that regulates the amount of light entering the eye. When the light is bright, the Iris closes the pupil, allowing less light to enter the eye, and when the light is dim, the pupil opens more, allowing more light to enter.

The pigmented or vascular layer includes the iris. It is the dark coloured, round structure found under the cornea.

Also Check Out:

| What is the function of the pupil? |

| What is the sclera of the eye? |

Iris: Structure and Function

The iris is located behind the cornea and above the eye lens. It is a part of the ciliary body, which is the thick anterior portion of the choroid layer of the eye. The color of the iris is determined by the amount and type of melanin pigment present in it, which can be brown, grey, green, blue, etc.

The iris is made up of two layers:

Stroma - the front pigmented, fibrovascular layer

Pigmented Epithelial Cells - Present at the back

The pupil is surrounded by the iris, which contains two sets of muscles. When the circular muscles contract, the pupil size decreases, and when the radially arranged muscles contract, the pupil size increases. This is how the iris acts as a diaphragm, controlling the size of the aperture and regulating the amount of light entering the pupil. This process is involuntary.

Thus, Iris plays a vital role in regulating the amount of light that is able to enter the Retina.

Eye Color

The iris is a highly pigmented structure that determines eye color. Common eye colors include hazel, brown, gray, blue, and green. The most important pigment that contributes to the iris color is melanin.

Muscles of the Iris

The Iris is a pigmented diaphragm with a central aperture - the Pupil - located in front of the lens. It serves to separate the anterior chamber, which is filled with aqueous humor, from the posterior chamber.

There are two muscles in the iris:

The Sphincter Pupillae is a circular muscle that constricts the pupil in bright light, provided by the parasympathetic fibres from the oculomotor nerve.

The Dilator Pupillae is a muscle of the iris that expands the pupil’s opening upon contraction, which is provided by the sympathetic fibres.

Frequently Asked Questions

The Colour of the Human Iris is Usually Brown or Blue

The pigmentation of human irises can range from black to light brown, depending on the concentration of melanin in the iris pigment epithelium, the amount of melanin in the iris stroma, and the cellular density of the stroma.

What are the two layers of the iris?

The two layers of the iris are the stroma and the epithelium.

The stroma is the front pigmented fibrovascular layer, beneath which the pigmented epithelial cells are present. These two layers make up the iris.

Iris is part of the genus Iris in the family Iridaceae.

The iris is the most anterior part of the uvea, which is a heavily pigmented structure that is the middle layer of the eye. Beneath the uvea lies the white part of the eye – the sclera. It comprises the iris, choroid and ciliary body.

What is iridology?

Iridodiagnosis, also known as Iridology, is a type of alternative medicine that examines the colors, patterns, and other characteristics of the iris to determine a patient’s overall health.

The Radial Muscle of the Iris is a smooth muscle that helps to control the size of the pupil by contracting or relaxing.

The radial muscle of the iris, or the iris dilator muscle, are smooth muscles of the eye which radially run in the iris and hence serve as a dilator.

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