Abstract: A device and method for comparing and correlating two or more portions of similar or disparate test data allows a doctor or technician to easily diagnose and/or treat a condition or defect. A device or method embodying the invention can be used for diagnosing vision disorders by correlating visual sensitivity or acuity data to images or data corresponding to biological structures responsible for vision. Such a method allows a doctor to easily identify defects or conditions of a biological structure that causes a loss of vision. In one embodiment of the invention, optical sensitivity data and biological structure data may be stored in multiple data layers, and the data layers can be compared to one another to identify pattern matches between data layers. Similar methods can be used to compare and correlate any two or more types of similar or disparate types of test data. Also, combined presentations of two portions of data can be used to selectively apply treatment to a target tissue.

Abstract: A videokeratograph has a placido disc with rings concentric about a central axis, a center positioned on the central axis, and an observation opening at the center. A plurality of fixation points are positioned in the placido disc spaced from the center opening and distributed circumferentially around the central axis, whereby rings on the placido disc spaced from the center are reflected from the central zone of the cornea. A video camera positioned on the center axis behind the placido disc observes an image of the placido disc reflected from the cornea. A processor coupled to the video camera determines the shape of the central zone of the cornea.

Abstract: An apparatus assists a user of a placido-based eye observation system to place the placido at an optimum distance from an observed eye. A light source is configured as a point source. The light source and a CCD camera are attached to the placido at opposed locations that are spaced from the viewing axis, but symmetric with respect to it. Light is emitted by the source towards the eye, and reflected by the apex of the cornea of the eye on the main axis. The reflected source light appears in the field of view of the CCD camera as a bright point image. The location of the point image within the field of view informs how far away the eye is from the placido. The placido is moved until the point image is positioned within the field of view at a reference position. In a manual embodiment a screen shows what is in the field of view, and an operator looks at the screen and uses a joystick to control movement of the placido.

Abstract: A device and method for comparing and correlating two or more disparate types of test data allows a doctor or technician to easily diagnose a condition or defect. A device or method embodying the invention can be used for diagnosing vision disorders by correlating visual sensitivity or acuity data to images or data corresponding to biological structures responsible for vision. Such a method allows a doctor to easily identify defects or conditions of a biological structure that causes a loss of vision. For instance, perimetry data which is indicative of visual sensitivity may be superimposed onto a fundus image of an eye to create a combined presentation of the data. In the combined presentation, the perimetry data overlies corresponding physical structures shown in the fundus image that give rise to the indicated optical sensitivities. The biological structure data may include an image of an eye, or an image of an optic nerve or a portion a brain responsible for processing optical data.