Abstract: This invention relates to certain improvements in the art of keratometry and, more particularly, to the use of television techniques to determine the shape of the corneal surface of an eye in essentially real-time. Paired television images of diffuse reflections from the cornea are produced by projecting an infra-red illuminated pattern onto the cornea. These diffuse reflections are compared by triangulation to define the corneal contour. The resultant data are processed by a conventional microcomputer to derive surface contour for display, the shape data so generated in a form for instant use. Compensation for image brightness at each location is provided by altering projected image brightness to compensate for inherent non-linearity of diffuse image brightness versus position in the image plane. The liberalization reduces the complexity of the digital signal processing required for producing a contour map of the cornea.

Abstract: An ophthalmic pachymeter which is highly effective in aiding in the determination of thickness and the optical density of the cornea of an eye on a real-time basis. The pachymeter therefore lends itself to effective employment in aiding in radial keratotomy and other surgical procedures with respect to the eye. The ophthalmic pachymeter of the invention has three major subsystems which include a television camera, a multiple slit projector and an associated processing and display system. In a broad form, the invention comprises illuminating a selected portion of the cornea, moving a slit across the cornea and generating Tyndall image ray paths for enabling analysis of the optical density of the cornea and the thickness of the cornea. This is accomplished through a series of digitally-encoded television images of the optical section of the cornea produced by a multiple slit projector and which images are then subjected to digital analysis.

Abstract: An ophthalmic instrument, in the nature of a pachymeter or densitometer, and which is used for ascertaining the thickness and relative optical density of the cornea of the eye on a real time basis. The instrument comprises a television camera and a multiple Scheimpflug corrected slit projector and an associated processing and display system. A number of digitally encoded television images of the optical section of the cornea are subjected to digital analysis. A density map may be constructed from the data derived in the digital analysis and produced for display either by a printer or display member. The display may be a three-dimensional plot of the frontal surface shape, local thickness, posterior surface contour and optical density of the cornea. A method of using the ophthalmic instrument and of making ophthalmic determinations is also disclosed.

Abstract: An electromagnetic flow probe for measuring fluid flow, and featuring interchangeable magnet and electrode lumen structures. A complex electrode lead pattern is incorporated in a lumen unit through which the fluid flow is conducted. The magnet structure is equipped with a magnetic field adjustment capability, and adjustable alignment lugs for receiving the lumen unit.