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Your Eyes and Cornea Problems

What Conditions Can Damage the Cornea?


Keratitis is an inflammation of the cornea that sometimes occurs with infection after viruses, bacteria, or fungi enter the cornea. These microorganisms can enter the eye after superficial or deep injuries, causing infection, inflammation, and ulceration of the cornea. Though uncommon, this type of infection can also arise after injury from wearing contact lenses.

Symptoms of keratitis include:

  • Severe pain
  • Blurred vision
  • Tearing
  • Redness
  • Extreme sensitivity to light
  • Discharge

Treatment usually includes antibiotic or antifungal eye drops. Sometimes, antiviral drugs and steroid eye drops are necessary.

Ocular Herpes (Herpes of the Eye)

Herpes is a viral infection of the eye, that may, like fever blisters, recur. The main cause of ocular herpes is the herpes simplex virus I (HSV I), the same virus that causes cold sores, but it can also result from the sexually transmitted herpes simplex virus II (HSV II) that causes genital herpes.

Ocular herpes produces sores on the surface of the cornea and, in time, the inflammation can spread deeper into the cornea and eye.

There is no cure for ocular herpes, but it can often be controlled with the use of antiviral drugs or steroid eye drops.

Herpes Zoster (Shingles)

Shingles is a recurrence of the chickenpox virus in people who have already had the disease. After a bout of chickenpox, this virus usually remains inactive within the nerves of the body. It can later travel down these nerves, infecting specific parts of the body, like the eye. Herpes zoster can cause lesions on the cornea. Corneal lesions usually heal by themselves, but antiviral treatment and/or topical steroid eye drops may reduce the inflammation.

Shingles can occur in anyone exposed to the chickenpox virus, but there is an increased risk in:

  • Older adults, especially over age 80
  • People with a weakened immune system

See your doctor if you have any symptoms of shingles. 

Corneal Degenerations

There are several types of corneal degenerations, diseases that can cause progressive structural problems with the cornea including:

  • Keratoconus

Keratoconus is a progressive disease in which the cornea thins and changes shape. Sometimes occurring as early as adolescence, this disease changes the curvature of the cornea, creating either mild or severe distortion, called astigmatism, and usually nearsightedness. Keratoconus may also result in swelling and scarring of the cornea and vision loss.

Factors associated with keratoconus include:

    • Genetics (a person can inherit a tendency for the condition from a parent)
    • Eye trauma (for example, from extensive rubbing of the eyes)
    • Eye diseases, such as retinitis pigmentosa, retinopathy of prematurity, vernal keratoconjuncitivitis
    • Other diseases, like Down syndrome, osteogenesis imperfecta, Addison's disease, Leber's congenital amaurosis, and Ehlers-Danlos syndrome

At first, keratoconus can be corrected with glasses or soft contact lenses. But, as the disease progresses, you may need to wear rigid gas permeable contact lenses. In approximately 10% to 15% of patients with keratoconus, a corneal transplant may also be necessary.

During a corneal transplant, the damaged cornea is replaced with a donated cornea. This operation is successful in about nine out of 10 people with advanced keratoconus. Even after a transplant, you will still most likely need glasses or contact lenses to see clearly.

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