About Your Eye

Basic Anatomy of a Normal Human Eye

Cornea

The cornea is the transparent front window of the eye. It is a thick, nearly circular structure covering the lens. The cornea is an important part of the focusing system of the eye.

Iris

The colored membrane of the eye. The iris is located between the cornea and the lens.

Pupil

The round black hole in the centre of the iris. The size of the pupil changes automatically to control the amount of light entering the eye.

Lens

A transparent structure located behind the iris. It focuses light rays entering through the pupil in order to form an image on the retina. If the lens becomes cloudy due to a cataract, the lens can be replaced with a plastic lens.

Retina

A thin multi-layered membrane which lines the inside back two-thirds of the eye. It is composed of millions of visual cells and it is connected by the optic nerve to the brain. The retina receives light and sends electrical impulses to the brain that result in sight.

Macula

An area of the eye near the centre of the retina where visual perception is most acute. The macula is responsible for the sharp, straight-ahead vision that is used for seeing fine detail, reading, driving and recognizing faces.

Optic Nerve

Cable-like structure composed of thousands of nerve fibers that connect the macula and retina with the brain. The optic nerve carries electrical impulses from the macula and retina to the processing centre of the brain where they are interpreted into clear, colorful sight.