Corneal topography is a method of corneal curvature examination assisted by computer analysis. A corneal topographer projects a series of illuminated rings onto the corneal surface, which are reflected back into the instrument. The reflected rings of light are analyzed by the computer and a topographical map of the cornea is generated. The topographical map and computerized analysis reveals any distortions of the cornea, such as is keratoconus or corneal scarring, as well as the corneal curvature and meridians of astigmatism. This diagnostic procedure is essential for patients being considered for refractive surgical procedures (such as LASIK) and may even be necessary in the follow-up of some patients who have undergone refractive surgical procedures.