Your cornea is the clear, dome-shaped window at the front of your eye. It focuses light into your eye. Keratoconus is when the cornea thins out and bulges like a cone. Changing the shape of the cornea brings light rays out of focus. As a result, your vision is blurry and distorted, making daily tasks like reading or driving difficult.
Doctors do not know for sure why people have keratoconus. In some cases, it appears to be genetic (passed down in families). About 1 out of 10 people with keratoconus have a parent who has it too. Keratoconus is also associated with:
Keratoconus often starts when people are in their late teens to early 20s. The vision symptoms slowly get worse over a period of about 10 to 20 years.
Keratoconus often affects both eyes, and can lead to very different vision between the two eyes. Symptoms can differ in each eye, and they can change over time.
In the early stage, keratoconus symptoms can include:
In later stages, keratoconus symptoms often include:
Keratoconus usually takes years to go from early- to late-stage. For some people, though, keratoconus can get worse quickly. The cornea can swell suddenly and start to scar. When the cornea has scar tissue, it loses its smoothness and becomes less clear. As a result, vision grows even more distorted and blurry.
A routine eye exam may cause a suspicion of keratoconus, but it is best diagnosed by special scans of your cornea. Your optometrist or ophthalmologist will review these scans for information about thickness and curvature to diagnose keratoconus and monitor for progression.
Keratoconus treatment depends on your symptoms. When your symptoms are mild, your vision can be corrected with eyeglasses. Later you may need to wear special hard contact lenses to help keep vision in proper focus.
Here are other ways that your ophthalmologist might treat keratoconus:
With keratoconus, try to avoid rubbing your eyes. This can damage thin corneal tissue and make your symptoms worse.
If you have itchy eyes that cause you to rub, speak to your ophthalmologist about medicines to control your allergies.