Keratoconus is a deterioration of the fibrous structure of the cornea with gradual bulging from the normal round shape to a cone shape. This condition causes decreased visual acuity . It is frequently discovered during adolescence.

Causes, incidence, and risk factors

The cause is unknown. Keratoconus is more common in contact lens wearers and nearsighted eyes. Some researchers believe that allergy may play a role.

Signs and tests

Keratoconus can usually be diagnosed with slit lamp examination of the cornea. Early cases may require corneal topography, a test which involves making a stereo image which gives a topographic map of the corneal curvature. When keratoconus is advanced, the cornea may be thinner in areas and this can be measured by pachymetry.

Treatment

Contact lenses are the primary treatment and are satisfactory treatment for most patients with keratoconus. Severe cases may require corneal transplantation .

Expectations (prognosis)

Vision can be corrected in most cases with contact lenses. Where corneal transplantation is needed, results are usually good after a long recovery period.

Complications

Patients with keratoconus should not have laser vision correction. Corneal topography is usually done before laser vision correction to eliminate this risk.

Calling your health care provider

Young persons whose vision cannot be corrected to 20/20 with glasses should be evaluated by an eye doctor experienced with keratoconus.

Prevention

There are no preventive measures. Some specialists believe that patients with keratoconus should have aggressive treatment of ocular allergy and should be instructed not to rub their eyes.