Which term refers to the colored part of the eye?

• A. Cataracts
• B. Tinnitus
• C. Iris
• D. Sclera

Answer: (C)

The colored part of the eye is the iris. It’s a pigmented ring that surrounds the pupil and lies between the cornea and the lens. Its main job is to regulate how much light enters the eye by changing the size of the pupil. This happens through two smooth muscle groups: the dilator pupillae expands the pupil in dim light or during arousal, while the sphincter pupillae contracts the pupil in bright light or when the parasympathetic system is active. The iris also gives each person their eye color due to melanin in the surrounding tissue. The other terms refer to different structures or conditions: cataracts involve clouding of the lens, the sclera is the white part of the eye, and tinnitus is a ringing in the ears, not part of the eye.