Keratoconus

Keratoconus is a condition of the cornea that causes thinning and the development of a cone-shaped protrusion. It leads to blurred vision and may cause sensitivity to light. Its prevalence varies among populations, reaching up to 1.2% in Europeans.

Keratoconus usually begins to develop between the end of adolescence and the thirties, and it most commonly affects both eyes.

The causes of keratoconus are unknown, although there are genetic and environmental factors involved in its development. It is estimated that around 1 in 10 people have a family history of keratoconus, and the environmental risk factors described to date are:

• Habitually rubbing the eyes vigorously.
• Presence of eye allergies.
• Having certain conditions such as retinitis pigmentosa, Down syndrome, Ehlers-Danlos syndrome, Marfan syndrome, hay fever, and asthma.

Generally, keratoconus affects both eyes, although it may produce different symptoms in each. Symptoms appear progressively, and among the most common are:

• Blurred vision
• Slightly distorted vision where straight lines may appear bent or wavy
• Increased sensitivity to light
• Redness or swelling of the eyes
• Worsening of myopia and/or astigmatism
• Poor fitting of contact lenses

There are no effective measures to prevent the onset of keratoconus, although managing eye allergies and avoiding rubbing the eyes may help prevent its worsening. Once it has developed, contact lenses are the primary treatment, although they do not stop the progression of the condition. The only effective surgical treatment to date is corneal transplantation.