Keratoconus (ker-uh-toe-KOH-nus) occurs when your cornea â the clear, dome-shaped front surface of your eye â thins and gradually bulges outward into a cone shape.
A cone-shaped cornea causes blurred vision and may cause sensitivity to light and glare. Keratoconus usually affects both eyes and generally begins to first affect people ages 10 to 25. The condition may progress slowly for 10 years or longer.
In the early stages of keratoconus, you can correct vision problems with glasses or soft contact lenses. Later you may have to be fitted with rigid gas permeable contact lenses or other types of lenses. If your condition progresses to an advanced stage, you may need a cornea transplant.
Keratoconus care at Mayo Clinic