Definition: Measurement of the anterior surface of the cornea, its curvature and shape. It is used often to diagnose keratoconus and other corneal diseases, and corneal changes after keratotomy and keratoplasty. A significant application is in the fitting of contact lenses. In performing corneal topography, many different techniques can be employed: keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing, videokeratography, etc.