Phoenix Laser Systems, Inc.

Charles F McMillan

H Alfred Sklar

Alan M Frank

Olga M Ferrer

Carl F Knopp

William D Fountain

Paul Harriss

Steven Schiffer

Stewart A Brown

Fred Rienecker

An improved apparatus and technique are disclosed for illuminating the cornea with points of light for analysis of the specularly reflected return light in determining the shape of the cornea. In combination with an optical illumination system which forms real images of points of light inside or in the path of the objective lens, the system of the invention includes a plurality of real light source points optically peripheral to the real image points and physically outside to the objective lens. The sources of the point light sources may be optical fibers or LEDs arranged in an array which optically extends radially outward from the objective lens, although the external points may be forward or back from the objective lens. The two types of point light sources are generally registered in a pattern and together form an ordered geometric array for providing paraxial reflections off the cornea over a wide area of the cornea, including both central and peripheral areas of the cornea.

Illumination of the cornea for profilometry

The present invention describes a technique and apparatus for finding spots in an image with substantial noise making it difficult to identify without specialized noise suppression algorithms. In the context of determining corneal shape, as an example of the technique, the reflections of point light sources in or on the cornea have long played a diagnostic role. The image analysis technique described applies the tools of mathematical morphology and prior information about the shape of illumination patterns to remove noise and isolate the points of interest for further mathematical analysis. The output from the technique is a set of pairs matching the detected points in the image with the known location of the illumination.

Apparatus and method of identifying signals in biological tissues

A system for effecting precision laser surgery includes an intensified surgical video microscope directed at the tissue to be operated upon and having zoom capability. The surgical microscope presents a microscopic image on a video screen in front of the surgeon. Preferably, the video screen is divided into multiple separate sections, with the microscopic video image in one section and precise cross sectional and plan views indicating location presented in the other sections of the screen. These additional views may be generated using Moire interferometry by projecting a Ronchi ruling on the surface of the tissue, in viewing the projection with a camera to obtain all necessary information for contour tracking of the subject surface. Interior elements and interfaces of, for example, the eye are also sensed by a light beam and precisely located and mapped by a computer forming a part of the device. The imaging system of the invention enables the surgeon to have before him abundant visual information on the video screen with indication of precisely where, in three dimensions, a focused surgical laser beam is directed at any time. The system also includes tracking system for following the movements of the subject tissue, for example an eye during surgery. The tracking system is fast enough to track such movement, preferably at the maximum repetition rate of the laser plus a sufficient margin for safety, but at all times faster than the frame rate for the video displays at which the video screen is retraced.

Method and apparatus for precision laser surgery

An ophthalmic diagnostic instrument determines the shape of the cornea through projection of an image onto the cornea through the optics of the diagnostic instrument. The instrument and the method of the invention involve folding a projected pattern of discrete separated point light sources so that the pattern is projected toward the eye coaxially with return collected light reflected off the cornea. The instrument avoids any need for a pattern light source directly adjacent to the eye, and provides the surgeon or other eye care specialist with a real time image accurately displaying the shape of the cornea. The surgeon is thus able to monitor the corneal shape prior to surgery, to monitor its changes during the course of the surgery, and to further monitor the cornea in post operative stages. In a specific embodiment of the invention, a real image of the pattern of point light sources is formed inside or very closely in front of the objective lens of the system so that the objective lens becomes a field lens and the angle of view of the system is enlarged.

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Livermore, CA, United States of America

Charles F McMillan