Keratoconus

Keratoconus is a condition affecting the cornea, the clear front window of the eye that normally focuses light allowing you to see clearly. In keratoconus, the cornea becomes progressively thinner and protrudes, causing distortion of your vision.

It is an uncommon condition, affecting about 1 in 2000 people. It is often diagnosed in the teenage years and gradually progresses until a person reaches their late 30s or 40s when the condition tends to stabilise.

Keratoconus is usually present in both eyes, although it may be worse in one eye than the other. The symptoms include:
• blurred vision and distortion
• glare
• frequent changes in glasses or contact lens prescriptions with increase in myopia (short sightedness) and astigmatism (corneal irregularity)
• occasionally, rapid progression of keratoconus can lead to sudden swelling and ‘whitening’ of the cornea leading to a sudden reduction in vision, light sensitivity and a red eye. This is caused by a tiny break in one of the layers in the cornea allowing the cornea to swell. It gradually heals over several months and leaves a scar on the cornea

The diagnosis of keratoconus is most commonly made by an examination of the eye, including taking images of the front of the eye that show the shape of the cornea (corneal topography). Changes over a period of time in your glasses prescription and in the corneal topography help us determine if your keratoconus is progressing. A regular comprehensive eye examination (at least yearly) is therefore important.

The cause of keratoconus is still unknown. There are several risk factors that have been found to be associated with the condition, for example:
• excessive eye rubbing
• a history of allergy, or periocular eczema
• a family history

To improve your vision, glasses in the early stages may be sufficient to improve your vision. However, as keratoconus progresses, rigid, gas permeable contact lenses may be required. In the most advanced stages, a corneal transplant may be necessary if there is significant corneal scarring and/or a contact lens cannot be fitted to improve the vision.

While there is no cure for keratoconus, people with progressive keratoconus may be suitable for corneal collagen cross-linking. This is a treatment that may stop the progression of keratoconus. A separate information sheet on cross-linking is available.

Eye drops may also be prescribed if you have symptoms of allergy. It is important that you avoid excessively rubbing your eyes as this may cause the keratoconus to progress more rapidly.