A photokeratoscope is described which makes it possible to record in a single photographic exposure the contour of the entire corneal surface of the eye. This has been accomplished by using a hemispherical object surface located such that its center of curvature coincides with the center of curvature of the cornea being photographed. The reflection of this surface is photographed through a small hole in the object surface. A brief history of the development of photokeratoscopy is presented. Photographs taken thus far verify the spherical nature of the central zone of the cornea.
HENRY A. KNOLL, RUSSELL STIMSON, and CARROL L. WEEKS, "New Photokeratoscope Utilizing a Hemispherical Object Surface," J. Opt. Soc. Am. 47, 221-222 (1957)