Abstract: A Keratometer for ascertaining the shape of the corneal surface of the eye comprises a television camera with associated processing circuitry. The television camera receives a reflection of a target such as placido's disc from the surface of the cornea. The television image of the reflection of the placido disc from the corneal surface is subjected to digital analysis after treatment in an edge detector. The edge detector reduces the number of data points that must be processed to define the radius of each ring in the reflected placido disc image. The resultant data are processed to derive surface contour and to provide a display in tabular, graphic or pictorial form of the contour data so generated.