Above: One of the instruments used to perform corneal mapping
Right: A sample of what the doctor views and interprets
Corneal topography, also known as photokeratoscopy or videokeratography, is a non-invasive medical imaging technique for mapping the surface curvature of the cornea, the outer structure of the eye. Since the cornea is normally responsible for some 70% of the eye's refractive power, its topography is of critical importance in determining the quality of vision. Another way to think of this information is as a map of the hills and valleys on the front surface of your eye, which helps your doctor custom-fit contact lenses, among other things.
The three-dimensional map can assist in the diagnosis and treatment of a number of conditions, including keratoconus, in planning refractive surgery such as LASIK and evaluating its results, and in assessing the fit of contact lenses. Corneal topography allows your doctor a measurement that is thousands of times more detailed than keratometry. This procedure is carried out in seconds and is completely painless.