Information on the Iris in Your Eye

The iris is the colored part of the eye.

The iris is the visible, colored part of the eye. It controls the pupil, a small opening that expands and contracts to allow more or less light to enter the eye.

Location

The iris exists near the front of the eye, behind the cornea and in front of the lens.

Components

The iris is made up of two sheets of smooth muscle that can dilate and contract. It is covered in a fluid called the aqueous humour.

Function

The iris controls the size of the pupil, which lets light into the eye. In places with bright light, the pupil becomes smaller; in darker situations, it enlarges.

Pigmentation

The iris is the colored part of your eye. If a person has green eyes, they actually have green irises. Iris color is determined by the amounts of eumelanin and pheomelanin present there.

Disease

Inflammation of the iris, referred to as iritis or anterior uveitis, can cause the iris to stick to the cornea. This can lead to secondary glaucoma and blindness.

Fun Fact

You can use a flashlight to see how the iris and pupil work. Shine a flashlight into your eyes or your friend's eyes, and the pupils will become smaller. When the light is removed, the pupils will become larger.

References

• Kidshealth.org: Your Eyes
• Encyclopedia Britannica: Iris (eye)
• Webvision: Gross Anatomy of the Eye