Abstract: Color-coded corneal topographic information contained in a polar plot of plurality of different traces taken over the corneal surface, such as that disclosed in the U.S. Pat. 4,863,260, is reprocessed to present the color topographic map in a "hills and valleys", Cartesian coordinate display; polar position being presented along the x-axis and elevation being presented along the y-axis. The different circular traces are separated one from the other in a perspective dispersion to emphasize the elevation data with the more apical traces being presented at one end and the more limbal trace being presented at the other end of the perspective dispersion.

Abstract: A computerized system which enables the contact lens fitter to select a contact lens by specifying its "base curve" and diameter and then to obtain a visual representation of how that lens would fit the cornea of a specific patient using a simulation of the traditional fluorescein dye procedure. The patient's corneal contours are electronically stored, having been ascertained, for example, using the image scanning technique disclosed in U.S. Pat. No. 4,863,260. The contour of the contact lens is positioned to a predetermined point over the contour of the corneal surface and iteratively rotated about two axes to establish a minimum average clearance. At this point, the clearance is depicted by a color display analogous to that which would be obtained using the actual contact lens on the patient's cornea with the fluorescein dye.

Abstract: A keratoscopic instrument capable of automatically compensating for the different optical characteristics exhibited by any of a set of mechanically interchangeable illuminated ring devices without manual recalibration includes on the base portion of each light ring device a plurality of distinctive, light pervious, machine-readable indicator spots illuminated from the keratoscope light source and arranged in a code indicative of the optical characteristics of the ring device in place. Marking information is detected and communicated to a computer controlled image processing system wherein the detected information is automatically utilized, in conjunction with other input data, to process the image.

Abstract: Apparatus and method for accurately quantifying the instantaneous radius curvature of a large plurality of points on the corneal surface is disclosed. A video image of the corneal surface accurately positioned at a predetermined point on the optic axis of measurement is obtained. The predetermined point is defined by intersecting low power laser beams. The video image is radially scanned from an original position at point defined by the intersection of the visual axis with corneal surface. Accurate measurements of the two-dimensional image radii of a plurality of illuminated mires reflective upon the corneal surface are made and corrected for camera distortions, quantization error and the different magnification occurring for different size corneas. The instrumentation is calibrated by using a plurality of mirror-like spheres of precisely known spherical radii.