Keratoconus is a degeneration that affects the cornea, the clear tissue located at the front of the eye. The normal corneal surface is smooth and aspheric, whereas the keratoconic eye is more like a cone; there are areas of thinning and steepening. The resulting corneal irregularities cause visual distortion which can no longer adequately be corrected with eyeglasses.
Although there is no gender predilection, this condition is typically revealed around puberty, and can progress into the 4th to 5th decade of life. There is believed to be a genetic component to keratoconus, but factors that are contributory include eye rubbing. Patients with collagen disorders are more likely to have this condition, since the cornea is mostly made of collagen fibers.
Patients who present with keratoconus have had a history of constantly changing prescriptions, usually with moderate to high amounts of astigmatism. Some patients are unable to achieve good, useable vision through their glasses or soft contact lenses. Most are unable to tolerate their contact lenses for many hours. Many patients with this condition experience blurry vision, haloes, and glare.
Patients, who are examined in office, will undergo a corneal topography (map), slit lamp evaluation, and refraction. These elements of the eye exam will reveal any underlying corneal condition, inclusive of keratoconus.
Untreated keratoconus can lead to scarring of the cornea and progressive corneal distortion. This can lead to a permanent reduction in vision, even with corrective devices, such as glasses or contact lenses.
Contact lenses remain the primary mode of visual rehabilitation in keratoconus. There is no cure but updated clinical guidelines now indicate all patients who are risk for progression of this condition should undergo corneal cross linking, if they are good candidates. This typically aids in the patient wearing their glasses or contact lenses with greater success, but rarely eliminates them completely. All patients with keratoconus are thoroughly screened to ensure they are good candidates for these procedures to minimize any associated risks.