Keratoconus

Keratoconus (pronounced KEHR-uh-toh-KOH-nus) is an uncommon condition in which the normally round, dome-like cornea (the clear front window of the eye) becomes thin and develops a cone-like bulge.?

An eye with keratoconus

Keratoconus literally means ?cone-shaped cornea.?

The cornea is a very important part of your eye. Light enters the eye through the cornea, which refracts, or focuses, the light rays so that you can see clearly. With keratoconus, the shape of the cornea is altered, distorting your vision. Keratoconus can make some activities difficult, such as driving, typing on a computer, watching television or reading.

Normal versus keratoconic cornea

What are the symptoms of keratoconus?

Keratoconus usually affects both eyes, though symptoms in each eye may differ. Symptoms usually start to occur in people who are in their late teens and early 20s and may include:

  • mild blurring of vision;
  • slight distortion of vision;
  • increased sensitivity to light;
  • glare;
  • mild eye irritation.

The rate of progression varies. Keratoconus will often progress slowly for 10 to 20 years and then suddenly stop.

As the condition progresses, the most common symptoms include:

  • increased blurring and distortion of your vision;
  • increased nearsightedness or astigmatism;
  • frequent eyeglass prescription changes;
  • inability to wear contact lenses.

Occasionally, keratoconus can advance rapidly, causing the cornea to become scarred. Scar tissue on the cornea causes the cornea to lose its smoothness and clarity. As a result, even more distortion and blurring of vision can occur.

What causes keratoconus?

The cause of keratoconus is still not known. Some researchers believe that genetics play a role, since an estimated 10 percent of people with keratoconus also have a family member with the condition.

How is keratoconus treated?

Treatment often depends on the severity of the condition. During early stages, vision can be corrected with eyeglasses. As the condition progresses, rigid contacts may need to be worn so that light entering the eye is refracted evenly and vision is not distorted. You should also refrain from rubbing your eyes, as this can aggravate the thin corneal tissue and make symptoms worse.

When good vision is no longer possible with contact lenses, a corneal transplant may be recommended. This surgery is only necessary in about 10 percent to 20 percent of patients with keratoconus. In a corneal transplant, your ophthalmologist (Eye M.D.) removes the diseased cornea from your eye and replaces it with a healthy donor cornea.

A transplanted cornea heals slowly. It can take up to a year or more to recover good vision after corneal transplantation.

While a corneal transplant will relieve the symptoms of keratoconus, it may not provide you with flawless vision; however, of all conditions requiring corneal transplants, keratoconus has the best prognosis for clear vision.