Definition: An instrument that 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. A topographical corneal map gives eye care professionals information about the shape of the cornea similar to a manual keratometer, only much more precise. While a manual keratometer generally gives information only about the central cornea, a topographer measures the entire area including the peripheral cornea. It also aids eye care professionals in fitting contact lenses and performing laser vision correction.


