The cornea is a clear, dome-shaped surface that makes up the outermost layer of the eye.
The cornea contains no blood vessels and must receive nourishment from tears and the aqueous humor (a fluid that lies just behind the cornea). Although it seems to lack substance or function, it is in fact a highly-organized tissue. In fact, the cornea is composed of five unique layers:
- The Epithelium – Thin and nerve-filled, this is the outermost layer of the cornea. It blocks the passage of foreign substances and aids in the absorption of oxygen and nutrients from tears.
- Bowman’s Membrane – The second layer is composed of collagen. This layer can heal if injured, though large or centrally-located scars can cause vision loss.
- Stroma – The third and thickest layer is primarily composed of collagen and water. Its unique characteristics allows for light to be conducted while maintaining strength, elasticity and form.
- Descemet’s Membrane – This thin, strong film provides protection against infection or injury. It is made primarily of collagen (though different from that found in the stroma) and is easily repaired after injury
- Endothelium – This thin, innermost layer keeps the cornea clear. This layer is responsible for pumping fluid out of the stroma. Endothelial cells cannot be repaired or replaced by the body.
It is important to select an Ophthalmologist who is knowledgeable and experienced in detecting and treating corneal problems early in order to prevent long-term eye problems.