Corneal topography is the measurement of corneal curvature assisted by computer analysis. Rings of light are projected onto the front corneal surface, which then are reflected back to the instrument. The ring pattern is then computed and analyzed generating a relief map as well as a computerized analysis of the corneal surface. This information allows anterior corneal distortions to be detected. This may help in diagnosing diseases such as keratoconus and keratoglobus. As well, this aids in defining areas of corneal distortion seen in cases of ocular injury. This diagnostic procedure is also essential for patients being considered for refractive surgical procedures (such as LASIK).