Keratoconus is an eye condition which can cause blurred and distorted sight, as well as a sensitivity to glare and light.
The condition affects the cornea which is at the front of the eye. The cornea changes shape and becomes thin and cone shaped.
Keratoconus usually affects people in their late teens or twenties and may continue to progress for 10 to 20 years before the condition slows down. It is difficult to detect because it develops slowly over a period of time.
The condition may affect each eye differently and can occur in one eye or both. As the keratoconus becomes worse, the cornea bulges more, distorting the vision even further.