Corneal and External Diseases

Our fellowship-trained specialists provide medical and surgical management of all corneal diseases.

What is the cornea?

The cornea is the transparent, dome-shaped, outermost layer that covers the iris and pupil in the front of the eye. The cornea is as smooth and clear as glass and is strong and durable. It helps the eye in two ways:

  • The cornea, along with the eyelids, the eye socket, tears and the sclera or white part of the eye, shields the rest of the eye from germs, dust and other harmful matter. 
  • The cornea is the eye's outermost lens and functions like a window that controls and focuses the entry of light into the eye. The cornea contributes 65-75 percent of the eye's total focusing power.

What are some diseases and disorders that affect the cornea?

  • Allergies -Symptoms can include redness, itching, tearing, burning, stinging and watery discharge, although not typically severe enough to require medical attention.
  • Conjunctivitis (Pink Eye) - Symptoms can include swelling, itching, burning and redness of the conjunctiva, the protective membrane that lines the eyelids and covers exposed areas of the sclera or white of the eye.
  • Corneal Infections - The cornea can be damaged after a foreign object, such as a finger, has penetrated the tissues. Other times, bacteria or fungi from a contaminated contact lens can pass into the cornea. These situations can cause painful inflammation and corneal infections called Keratitis. Minor corneal infections are commonly treated with antibacterial drops. If the problem is severe, it may require more intensive antibiotic or anti-fungal treatment to eliminate the infection in addition to steroid eye drops to reduce inflammation.
  • Dry Eye - The continuous production and drainage of tears is important to the eye's health. Tears keep the eye moist, heal wounds and protect against eye infection. Dry eye causes the eye to produce fewer or lower-quality tears and is unable to keep its surface lubricated and comfortable. Artificial tears, which lubricate the eye, are the principal treatment for dry eye.
  • Fuch's Dystrophy - Occurs when endothelial cells gradually deteriorate without any apparent reason. This causes the cornea to swell and distort vision. Eventually, the epithelium also takes on water, resulting in pain and severe visual impairment. When treating the disease, physicians will first try to reduce the swelling with drops, ointments or soft contact lenses. When the disease interferes with daily activities, a corneal transplant may be necessary to restore sight.
  • Herpes Zoster (Shingles) - This infection is produced by the same virus that causes chickenpox. After an initital outbreak of chickenpox, the virus remains inactive within the nerve cells of the central nervous system. Sometimes, the virus will reactivate and travel to the head and neck. About 40 percent shingles outbreaks will infect the cornea. Unlike herpes simplex I, the varicella-zoster virus does not usually flare up more than once in adults with normal functioning immune systems.
  • Keratoconus - This disorder is a progressive thinning of the cornea. Keratoconus arises when the middle of the cornea thins and gradually bulges outward, forming a rounded cone shape. This abnormal curvature changes the cornea's refractive power, producing moderate to severe distortion (astigmatism) and blurriness (nearsightedness) of vision. Keratoconus usually affects both eyes and can be corrected with eyeglasses. As the astigmatism worsens, specially fitted contact lenses may be necessary to reduce distortion and provide better vision. In most cases, the cornea will stabilize after a few years without ever causing several vision problems, but in 10 to 20 percent of cases, the cornea will eventually become too scarred or will not tolerate a contact lens. If either of these problems occur, a corneal transplant may be needed.

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