What Is Keratoconus?

The term keratoconus means “cone-shaped.” Keratoconus is a condition in which the cornea (the clear front layer of the eye) slowly and progressively becomes steeper and thinner. This abnormal shape causes the light passing through the cornea to focus irregularly which in turn causes blurry vision, even with eyeglasses.


The most common first signs of keratoconus are glare and blurry vision. A careful eye examination allows the eye doctor to identify irregular astigmatism (an out of roundness of the eye). Upon a closer evaluation, the doctor identifies that the the irregular astigmatism is caused by keratoconus.


The exact cause of keratoconus has not yet been identified. It usually appears in individuals during their late teens or early twenties. The disorder usually progresses for 10 to 20 years. during which time the cornea steepens and thins, creating more severe irregular astigmatism. Although both eyes may be affected, one eye is usually worse than the other.

Risk Factors

Looking back at many records of patients with keratoconus, there are several things that repeatedly show up in patient histories:

  • Genetics may contribute to your risk of developing keratoconus.
  • Regular, vigorous eye rubbing is thought to add to development and progression of the disease, but this is not confirmed scientifically!

Diagnosis of Keratoconus

Although signs of keratoconus can be seen during a routine eye examination by your eye doctor, some additional testing can confirm the presence of keratoconus. A mapping device called a corneal topographer photographs the surface of the eye, and measures the curves of the cornea from its central point (visual axis) to the periphery of the cornea near the white of the eye.

Treatment of Keratoconus

  • Contact Lenses: Although there are no medicines known that will prevent progression of the disease, mild cases of keratoconus can be successfully treated with glasses or specially designed contact lenses.
  • PROSE contact lenses: A customizable oversized hard contact lens device called Prosthetic Rehabilitation of the Ocular Surface Ecosystem (PROSE) can also improve vision for many patients with keratoconus.
  • Surgery: When vision is no longer satisfactory with glasses or contact lenses, a corneal transplant may be recommended.
  • Intacts: In addition, intra-corneal rings have been approved by the FDA for the treatment of keratoconus. These crescent-shaped plastic rings are surgically placed into the outer edges of the cornea, causing the center of the cornea to be less irregular, and providing clearer vision.
  • Collagen Cross-linking: Collagen cross-linking is a new treatment that strengthens the cornea and may slow the progression of keratoconus. This treatment is currently being studied by the FDA.

Video: What is Keratoconus?