Keratoconus is a degenerative disease that affects the cornea. The cornea is the front window of the eye and is normally smooth and round. In patients with keratoconus the cornea becomes irregular, thin and cone shaped. The abnormal shape prevents the light entering the eye from being focused correctly and causes blurred, distortion vision. Glasses do not adequately correct the vision and often special contact lenses are used to provide a smooth surface in front of the cornea and give better vision. There are some new surgical options for patients who cannot tolerate these lenses.

Signs and symptoms

Blurred vision even with spectacles or contact lenses

Near sightedness and /or astigmatism

Problems with glare at night

Increased light sensitivity

Eye rubbing

Frequent changes in prescription for spectacles or contact lenses

Detection and diagnosis

Keratoconus typically begins at puberty and progresses into the mid thirties when it often slows and stops. It is often diagnosed by examining the patient with a slit lamp, special microscope, and taking measurements of the curvature of the front of the eye. There is no way to calculate how fast it will progress or if it will progress at all. Every eye is affected differently.  As keratoconus progresses the cornea bulges more and vision becomes more distorted.


Spectacles may be used to correct mild nearsightedness and astigmatism that is found in the early stages of keratoconus. As the condition progresses and the cornea continues to change shape rigid gas permeable contact lenses can be prescribed. These lenses can be very challenging to fit and require frequent checkups and lens changes to maintain good vision. Some ophthalmologists insert intacts into the front of the eye to flatten the cornea that has become too steep. Cross linkage is a procedure to try to stiffen and stabilize the cornea using vitamin drops and specialized light. In a small number of cases corneal transplant is necessary to replace the dangerously thin and distorted cornea with a healthy one.