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Understanding the Cornea

Prior to learning about the services we offer to treat and repair cornea conditions it is a good idea to familiarize yourself with the cornea part of the eye. The information below details what happens in this outermost layer of the eye and the common cornea diseases.

The cornea is the eye's outermost layer. It is the clear, dome-shaped surface that covers the front of the eye and plays an important part in the eye's visual acuity. The cornea is the transparent covers the iris and pupil in the front of the eye. Corneal tissue consists of five basic layers: epithelium, Bowman’s layer, stroma, Descemet’s membrane and endothelium. Although the cornea is clear, it contains a highly organized group of cells and proteins. Unlike most tissues in the body, the cornea contains no blood vessels to nourish or protect it against infection. Instead, the cornea receives its nourishment from the tears and aqueous humor that fill the chamber behind it.

The cornea, one of the protective layers of the eye, serves two functions:

  • First, along with the eyelid, eye socket, and sclera (white part of the eye), and the tear film, the cornea shields the eye from dust, germs, and other harmful matter.
  • Second, as the eye’s outermost lens, it is the entry point for light into the eye. When light strikes the cornea, it bends, or refracts, the incoming light onto the lens. The lens further refocuses the light onto the retina, a layer of light-sensing cells lining the back of the eye.

To see clearly, the cornea and lens must focus the light rays precisely on the retina. This refractive process is similar to the way a camera takes a picture. The cornea and lens in the eye act as would a camera’s lens. The retina approximates the film. If the cornea is unable to focus the light properly, then the retina receives a blurry image.

Diseases of the Cornea

  • Keratoconus - Keratoconus can cause considerable distortion of vision including double vision, streaking and sensitivity to light. It is a degenerative condition of the cornea that causes thinning and shifting from a normal gradual curve to more conical shape.
  • Dry Eye Syndrome - This is a condition where the eye does not produce the right amoung or quality of tears to keep the eye health and comfortable.
  • Corneal Dystrophies -Corneal dystrophy is a disorder that causes a layer of the cornea to cloud over and impair visual clarity. It is caused by a group of genetic disorders that generate abnormal material that accumulates in the cornea.
  • Microbial Infections (keratitis) - This condition is one in which the cornea becomes inflamed. It can be moderately painful, itchy and sometimes involves impaired vision.
  • Conjunctivitis ("pink eye") - A condition where the conjunctiva or the outermost layer of the eye is inflammed or infected by a virus or bacteria. It can also be caused by airborne irritants.
  • Ocular Herpes - Caused by the type 1 herpes simplex virus, this condition is a common, recurring viral infection distressing the eyes. This type of condition can cause inflammation and scarring of the cornea that sometimes is referred to as a cold sore on the eye.
  • Fuch's Dystrophy - This condition is a progressive disease affecting the cornea that reduces the number of endothelial cells that make up the inner layer of the cornea. These cells stop processing water and fluid starts to buld up and begin to cloud vision.

Cornea Procedures Offered

Your Regional Eye Associates Corneal Specialist and Surgeon is:

Dr. Heath Lemley