Your eye and common conditions

The visible parts of the eyeball are the white sclera and the colored iris. A membrane called the conjunctiva covers the sclera.

The clear cornea lies in front of the iris. The lens is connected to the ciliary body. Inside the eyeball is a clear substance called vitreous humor.

The retina, which underlies the choroid, changes light rays into electrical signals. The optic nerve carries the signals to the brain. The fovea centralis, a pit in the macula lutea, is the area of sharpest vision.

Diagram of the eye