Keratoconus is a progressive disorder that is characterized by thinning and cone-like bulging (steepening) of the cornea. In its earliest stages, keratoconus causes slight blurring and distortion of vision and increased sensitivity to glare and light due to irregular astigmatism. Symptoms usually first appear in the late teens and early twenties. Keratoconus may progress for 10-20 years and then slow down its progression. It can ultimately result in a dramatic decrease in the ability to see clearly with glasses. Rigid contact lenses are the primary method of treatment for mild cases. Advanced cases, characterized by severe steepening of the cornea and/or corneal scarring, are treated with corneal transplantation. A relatively new technology called INTACS may offer a less invasive option for the treatment of moderate to advanced keratoconus.