Keratoconus is a deterioration of the structure of the cornea with gradual bulging from the normal round shape to a cone shape.
The cause is unknown. Keratoconus is more common in contact lens wearers and people with nearsighted eyes. Some researchers believe that allergy may play a role.
Kymionis GD, Siganos CS, Tsiklis NS, et al. Long-term follow-up of Intacs in keratoconus. Am J Ophthalmol. Feb 2007;143(2):236-244.
Fay A. Diseases of the visual system. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 449