Computerized Interferometric Corneal Topographer

We will develop a new computerized corneal topography instrument based on the use of shearinginterferometry and digital phase-measuring techniques. The interferometric approach is capable of highmeasuring accuracy, one order of magnitude above that of commercially available computer-assistedkeratoscopes. It also surmounts many of the difficulties encountered by existing systems whichreconstruct the corneal surface from images of keratoscopic mires, especially in the case of irregularcorneas, whether diseased or following corneal procedures. A laboratory prototype system will bedesigned and constructed, based on the use of polarization shearing interferometry, solid state CCDimaging and microcomputer technology. Software will be developed, using new digital phase measuringtechniques capable of real-time measurement with submicron accuracy over large arrays of data points.Graphical displays will include outputs such as wire-mesh views, color contour maps and meridionalprofiles. Laboratory testing of the prototype will include estimation of the measuring accuracy usingcalibrated steel balls. The approach will be also assessed in terms of reliability, reproducibility, ease ofuse and cost effectiveness.