TreatKeratoconus Keratoconus is a degenerative eye disease that causes the cornea to thin and bulge, creating a cone-like irregular shape. Because the cornea is responsible for refracting most of the light that comes into the eye, any irregularity of the cornea can result in significant visual impairment. Keratoconus most often appears in a person’s late teenage years; although it has been diagnosed in people in their forties and fifties. The eye disease has been estimated to occur in roughly one out of every 2,000 people in the general population. No significant geographical, gender, ethnic, or social pattern has been established, and keratoconus occurs in all parts of the world.