Keratoconus

What it is

In keratoconus, the cornea becomes thinner and bulges forward into an irregular cone shape. This distorts the way light enters the eye, causing increasingly blurred and distorted vision. It often progresses slowly over years and usually affects both eyes.

Common symptoms

Symptoms often begin in the teens or early twenties.

• Blurred or distorted vision
• Increasing short-sightedness and astigmatism
• Glare and halos around lights, especially at night
• Frequent changes to your glasses prescription

Causes and risk factors

The exact cause is unclear, but it is linked to vigorous eye rubbing, a family history, allergies and conditions involving frequent eye rubbing. Avoiding rubbing the eyes is an important part of protecting the cornea.

Treatment

Early keratoconus can be corrected with glasses or soft contact lenses. As it advances, special rigid or specialist contact lenses give clearer vision. Corneal cross-linking can strengthen the cornea and slow or stop progression, and a corneal transplant may be needed in advanced cases.