Learn About Keratoconus
What is keratoconus?
Keratoconus is a condition that affects the cornea (front surface of eye). In keratoconus, the cornea progressively thins and bulges forward into a cone-shape. If the curvature or shape of the cornea is altered, it distorts the light rays that enter the eye. This ultimately causes blurred vision due to an increased amount of astigmatism. Usually the astigmatism is irregular, which makes it difficult to clearly read 20/20 even with glasses. Keratoconus typically affects both eyes, however, one might be worse than the other. In some severe cases, the cornea can swell and cause scarring. Corneal scars limit vision and may require a cornea transplant.
What are the symptoms of keratoconus?
The first, and most common, symptom of keratoconus is blurred or distorted vision. As the condition progresses, the vision typically decreases. Glare and photophobia (light sensitivity) are other common symptoms. When light enters an irregular-shaped cornea, the light rays bounce around in an unorganized manner, which leads to the glare and photophobia.
How is keratoconus diagnosed?
Keratoconus is diagnosed by using the following tools and tests:
– Keratometry: measures the curvature of the cornea
– Slit lamp examination: uses a magnified light to visualize the corneal thinning and protruding cone
– Corneal topography: maps the corneal surface and measures corneal thickness
– Vision test and refraction: determines the vision and glasses prescription
What are the risk factors for keratoconus?
Symptoms usually begin in a person’s early teens to mid-20s. The following risk factors may increase the chance of being diagnosed with keratoconus:
– Family history of keratoconus
– Frequent eye rubbing
– Certain medical conditions (Down syndrome, Ehlers-Danlos syndrome, allergies)
What is the treatment for keratoconus?
Glasses or soft contact lenses are usually the first method of treating the distorted vision that is associated with keratoconus. It is common for the prescription to change more frequently than it would in someone without keratoconus. If glasses or soft contact lenses do not provide adequate vision, the next step is rigid gas permeable contact lenses (hard contacts). In advanced stages of the condition, a cornea transplant is the final treatment option.
Corneal cross-linking is a new therapy developed to minimize the progression of corneal thinning associated with keratoconus. Fortified vitamin B drops (riboflavin) are vigorously applied to the cornea, which is then treated with ultraviolet light. This forms extra bonds that help strengthen the cornea with the goal of decreasing the amount of bulging early in the disease process. Early treatment and prevention provides the best outcome.