Keratoconus is a developed abnormality in which the cornea progressively becomes thinned centrally and bulges forward in a conical fashion.
It usually occurs in both eyes and is seen more often in females. It creates irregular astigmatism that cannot be corrected with eye glasses. Rigid contact lenses have been used to correct the visual defect.
If the patient is unable to be fitted properly with contact lenses because of high irregular astigmatism, keratoplasty (corneal transplant) is necessary to restore vision.