What is a Cornea?

The cornea, situated at the front of the eye, is the transparent dome of layered cells overlying the colored iris of the eye. In its normal state, the cornea is composed of thin layers of tissue that allows rays of light to pass through and be focused on the retina. The cornea and the lens of the eye, a separate structure located just behind the iris, are responsible for creating a sharply focused image on the back of the eye so that we can see clearly. The cornea is responsible for roughly two-thirds of the focusing power of the eye, with the lens responsible for the remainder.

Many eye conditions affect the cornea and may change its transparency. Injuries, infection, inherited conditions, or aging changes may cause clouding or distortion of the cornea with decreased or distorted vision.

Sometimes vision can be improved with glasses, a contact lens, or medications. However, when non-surgical treatment fails, a corneal transplant may be necessary to improve vision.