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.
The cornea is a very important part of your eye. As light enters the eye through the cornea, 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. Keratoconus can make some activities difficult, such as driving, typing on a computer, watching television or reading.
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.
The rate of progression varies. It will often progress slowly for 10 to 20 years and then suddenly stop. As the condition progresses, most common symptoms include:
- 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.
The cause of keratoconus 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.
Treatment will often depend 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 is recommended. This surgery is only necessary in about 10-20% of patients with keratoconus. In a corneal transplant, a cornea specialist removes the diseased cornea from your eye and replaces it with a healthy donor cornea.
While a corneal transplant will relieve the symptoms of keratoconus, it may not provide you with flawless vision; eyeglasses or contacts may still be needed to achieve your best vision.
