keratoconusKeratoconus (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. The name literally means "cone-shaped cornea."

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

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 twenties and may include:

  • mild blurring of vision;
  • slight distortion of vision;
  • increased sensitivity to light;
  • glare;
  • mild irritation.
  • increased blurring and distortion of your vision;
  • increased nearsightedness or astigmatism;
  • frequent eyeglass prescription changes.

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