Abstract: A system for facilitating tracking of a moving object is disclosed. The object has a feature associated therewith which is illuminated with ambient light. The system includes illumination means for illuminating at least the feature of the object with a tracking light. The system also includes detection means for detecting an image of the feature and for outputting signals corresponding to movement of the image. The signals have a first component due to the tracking light and a second component due to the ambient light. Further, the system includes filter means for filtering the second component from the signals and for outputting the first component of the signals so that the ambient light is discriminated from the tracking light and the moving object can be tracked using the first component of the signals.

Abstract: A surgical technique for removing corneal tissue with scanned infrared radiation is disclosed which utilizes short mid-infrared laser pulses to provide a tissue removal mechanism based on photospallation. Photospallation is a photomechanical ablation mechanism which results from the absorption of incident radiation by the corneal tissue. Since photospallation is a mechanical ablation process, very little heat is generated in the unablated adjacent tissue. The disclosed surgical system includes a scanning beam delivery system which allows uniform irradiation of the treatment region and utilizes low energy outputs to achieve controlled tissue removal. A real-time servo-controlled dynamic eye tracker, based on a multiple-detector arrangement, is also disclosed which senses the motion of the eye and provides signals that are proportional to the errors in the lateral alignment of the eye relative to the axis of the laser beam.

Abstract: The invention relates to a method and apparatus for uniquely and unambiguously aligning a patient's visual line of sight (LOS) to the optical axis of an ophthalmic instrument such as may be used for laser surgery or diagnostics. By the method of the invention, two alignment targets are imaged at different distances along the optical axis of the ophthalmic instrument. Viewing along the optical axis, a patient moves his or her eye until the two imaged targets are in alignment. When the two imaged targets are viewed in alignment by the patient, the patient's LOS is precisely aligned with the optical axis of the apparatus. By relying on the patient's ability to self-align, this technique ensures that measurements are taken within a reproducible reference frame that is unique to each patient but independent of the type of machine used.

Abstract: In use of laser radiation to ablate corneal tissue, to achieve a sculptured change in curvature of the optically used region of the cornea, a variable magnification (zoom) lens is combined with different sized apertures of an indexible mask to develop a relatively smooth profile for the changed curvature. The zoom-lens settings are varied in the course of cornea exposure through each of the succession of mask apertures. To do this, the range of zoom-lens magnification can always be less than 2:1, yet the zoom-lens system can effectively reduce to insignificance the stepped profiling that is inherent in reliance only upon the indexed aperture technique. Also described are techniques to achieve compensation for delivered flux-density variation as a function of instantaneous zoom-lens setting, and programmable control of the area of delivered flux density in a manner to correct for parabolic or other fall-off in delivered beam intensity as a function of radius outward of the axis of beam delivery.

Abstract: A contour measuring apparatus and method of using the apparatus is disclosed to measure the three-dimensional contour of a surface. A multi-point light source directs a plurality of light beams onto the surface to be measured. The light beams are reflected through a lens onto a photodetector to produce electro-optically measurable optical images. A structure is provided to determine the local radius of curvature of the surface at each desired point of incidence of individual light beams and the three-dimensional surface contour of the surface being measured. A calibration device is provided to reduce instrument errors of the apparatus. The calibration device includes a calibration surface with a known contour to be positioned in substitution of the surface being measured.

Abstract: A contour measuring apparatus and method of using the same is disclosed to measure the three-dimensional contour of a surface. Structure is provided to direct first light beams onto the surface being measured. Reflections of the first light beams from the surface are received for generating electrical output signals corresponding to electro-optically measurable optical images. The output signals are electrically processed to determine the radius of curvature of the surface being measured. A higher spatial resolution can be achieved without changing the spacing of the array of light points.

Abstract: A contour measuring apparatus and method of using the same is disclosed to measure the three-dimensional contour of a surface. Structure is provided to direct first light beams onto the surface being measured. Reflections of the first light beams from the surface are received for generating electrical output signals corresponding to electro-optically measurable optical images. Each of the images corresponds to the location of the first light beams. Structure determines the approximate location of the center of the surface being measured with respect to an optical axis extending through the contour measuring apparatus. The location determining structure comprises a component for directing a single light beam along the optical axis of the contour measuring apparatus onto the surface being measured so as to reflect to the means for generating electrical output signals.

Abstract: A beam intensity profilometer produces a fluorescent emission distribution having a spatial distribution linearly proportional to the local intensity of an incident UV beam shined into the profilometer. The spatial distribution of the UV beam is analyzed and displayed as a function of the fluorescent emission.

Abstract: In the context of ultraviolet-laser sculpting of the cornea to achieve optical correction through a newly shaped anterior surface, the invention subjects the laser beam to certain shaping and homogenizing operations prior to any attempt to specially characterize the beam for a particular sculpturing procedure. In a preferred embodiment, the shaping and homogenizing operations present a tolerably homogeneous beam of enlarged dimension, so that specialty-characterizing may proceed on a dimensional scale that is greater than the corresponding dimension of ultimate surgical delivery to the eye, thereby enabling greater control of the quality of specialty-characterizing. Provision is made for selectively monitoring the quality of the homogeneity and/or of the specially-characterized beam, with further provision for automated cutoff of laser beam delivery to an eye in the event that quality is not within predetermined limits of tolerance.

Abstract: An eye restraining device includes a ring-shaped element which contacts the sclera of an eye so that the cornea projects above the ring-shaped element. A second embodiment includes a head restraint including a plurality of adjustable engaging components for accommodating different sized heads.

Abstract: A contour measuring apparatus and method of using the apparatus is disclosed to measure the three-dimensional contour of a surface. A multi-point light source directs a plurality of light beams onto the surface to be measured. The light beams are reflected through a lens onto a photodetector to produce electro-optically measurable optical images. A structure is provided to determine the local radius of curvature of the surface at each desired point of incidence of individual light beams and the three-dimensional surface contour of the surface being measured. A calibration device is provided to reduce instrument errors of the apparatus. The calibration device includes a calibration surface with a known contour to be positioned in substitution of the surface being measured.

Abstract: An encoder for providing a conical array of temporally phased pulse beams. A pulse is inserted and continuously recirculated around an optical ring. The pulse is amplified during each circulation and a portion of the pulse is emitted at the end of each circulation. The encoder includes means for spatially separating each emitted pulse to provide a conical array of beams at a constant field angle relative to the optical axis of propagation.

Abstract: A passive compensating device which compensates for angular and translational misalignment errors in a polarized beam and assures the projected beam centroid remains at the same position. The device splits the incoming beam into two beams. Thereafter, optical orienting means disposed to intercept the two beams is operative to rotate the wavefront of both beams so that the composite beam exiting a combiner has two components wherein one component has its wavefront rotated 180.degree. about two orthogonal axes with respect to the other beam. Accordingly, the composite beam centroid is maintained at one position regardless of jitter of the beam entering the compensator device.