Patient Education

A growing library of easy-to-read informational pages about a host of common eye problems.


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Keratoconus 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. Keratoconus literally translates into ”cone-shaped cornea.”


The cornea is a very important part of your eye. It is transparent to allow light into the eye but it is also a very powerful lens, contributing 2/3 of the total lens power of the eye. Since it is a powerful lens even small irregularities can cause significant blurred vision.

By Madhero88 (own work) [CC-BY-SA3.0] via Wikimedia Commons

Who is at Risk for Keratoconus?

Anyone can be at risk for keratoconus, though this disease is usually pretty rare. However, some people may be at higher risk than others. For example, 10% of people with keratoconus also have a family member with the condition, suggesting some kind of genetic predisposition.

Also, it has been associated with excessive eye rubbing or wearing hard contact lenses for a long period of time. Any eye injury, as well as certain eye diseases (retinitis pigmentosa or retinopathy of prematurity), and some systemic diseases (such as Leber’s Congenital Amaurosis, Ehlers-Danlos, Down syndrome, etc.), have been shown to be associated with keratoconus as well.

What are the Symptoms of Keratoconus?

“KC simulation” by BillC

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:

  • Blurring of vision
  • Distortion of vision
  • Increased sensitivity to light
  • Glare
  • Double images or ghosting
  • Increasing near-sightedness / astigmatism
  • Corneal clouding in severe stages

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.

How is Keratoconus Treated?

Treatment depends on the severity of the condition. During the early stages, vision can be corrected with eyeglasses. As the condition progresses, rigid, gas permeable contact lenses can help to improve the symptoms by recreating the round shape of the normal cornea. Constant rubbing of the eyes should also be avoided if possible. When good vision is no longer possible with contact lenses, a corneal transplant may be recommended. This surgery is only necessary in about 10-20% of patients with Keratoconus, especially when scarring blocks the incoming light. In a corneal transplant, an Eye Surgeon removes the diseased cornea from your eye and replaces it with a healthy donor cornea. A corneal transplant is expected to improve the shape of the cornea but nearly all corneal transplant patients require a rigid gas permeable contact lens after surgery to achieve their best vision. You can read more about corneal transplants here. For more information please visit the website of the National Keratoconus Foundation at: