Abstract: An ophthalmologic apparatus including an illuminating light source, an annular index, and an optical system for projecting the index from an infinite distance to a cornea of an eye to be examined, in which the index is formed integrally with the projecting optical system.

Abstract: A scanning keratometer for the rapid and accurate measurement and mapping of the corneal curvature is disclosed. The keratometer has a monochromatic light source directing light to a scanner, preferably controlled by a microcomputer. The scanner directs the light to a holographic element functioning as a lens which in turn focuses the light to a fixed focal point forward of the holographic element independent of the area of the holographic element being illuminated. The subject's eye is position with respect to the fixed focal point so that a part of the light incident to the eye is reflected from the surface thereof again passing through the holographic element, to be deflected from the main optical axis of the system to a suitable area sensor. Assuming the subject's eye is properly positioned and the cornea surface matches the shape of an ideal cornea, the light incident to the cornea will be reflected in the same direction as the incident light, ultimately impinging on the center of the sensor.

Abstract: A method and apparatus in which a predetermined index is projected onto the cornea of an eye to be examined and the shape of the cornea determining the refractive power, the degree of astigmatism, the direction of astigmatic axis, etc. of the cornea is measured from the general elliptical shape of the image of the index reflected by the cornea. Independently of the center of the ellipse, arbitrary position coordinates of at least five points of the image reflected by the cornea are detected, whereby the elliptical shape is calculated without enhancing the alignment accuracy in a plane perpendicular to the optical axis. The image reflected by the cornea may be electrically detected by position detects such as CCDs, whereby automation of the measurement is provided, coupled with the later signal processing. A strobo light is used for the projection of the index.

Abstract: Apparatus and method for use in ocular surgery to enable the surgeon to determine the degree of self correcting astigmatism to apply to the eye during the suturing procedure. The apparatus comprises an ocular microscope provided with a device for directing a ring of light onto the anterior surface of the cornea of the eye such that the cornea will reflect the ring for viewing in the eyepiece of the microscope. The eyepiece is provided with means for determining the shape of the reflected ring and hence the degree of astigmatism applied to the cornea by the surgeon. In particular this means may be in form of a comparison ring which may be viewed in the same field of view as the reflected ring and being adjustable by the surgeon to provide a series of comparison rings for comparison with the reflected ring and corresponding to successive degrees of corneal astigmatism.

Abstract: A curvature measuring apparatus is provided for measuring the radii of curvature of a curved surface, particularly a human cornea or a contact lens. The apparatus comprises an illuminating optical system which illuminates the surface to be measured. The optical system includes a light source for forming a pattern of radiating beams of at least two groups, with each group being comprised of at least two parallel straight lines in a virtual plane. The straight lines in one group are different in directions of arrangement from the straight lines in the other group, and each group includes at least one line whose characteristics are substantially different from the other lines in the group to serve as a reference line. A collimator lens orients principal rays of illuminating beams of light emitted from the light source through a pin hole arranged on an optical axis, to be parallel to the optical axis so as to illuminate the surface to be measured by the illuminating beams of light.

Abstract: An optical instrument which measures with great accuracy certain anatomical dimensions of an eye utilizing finite light beams which strike the eye from pre-determined angles and distances. The instrument measures, among other things, the critical sagittal depth of the eye where the finite light beams converge at a recognizable point. The measurements provide optimal fitting of a contact lens to the eye.

Abstract: A device for determining the topography of the cornea surface, realizing a method for determining the cornea surface topography, comprises a frame carrying a light source, an objective lens, a light detector, and an array of measuring marks. Said array of measuring marks is a combination of two mark groups, one group being a plurality of ring-shaped marks arranged one after another, axially along the frame and perpendicular to the lens optical axis, while the other group is a plurality of lines arranged lengthwise along the frame to intersect every ring mark and produce, in the light detector, an image consisting of concentric annular patterns and intersecting lines of the radial grid. After a flat image of the array image is obtained, coordinates of image points are measured for specific topographic angles, and corrections are introduced in accordance with the curvature of the radial grid lines.

Abstract: An astigmatic ruler for determining an amount of astigmatism associated with a cornea of a human eye by qualitative methods comprises a target member having a plurality of apertures therethrough. One of the apertures is circular and the remaining apertures are elliptical in shape. The elliptical apertures are associated with various incremental amounts of astigmatism. The target member is adapted to be positioned between the eye and an illuminated surgical microscope such that light is projected through a selected aperture and onto the eye. The amount of astigmatism associated with the eye is indicated when a selected aperture is presented to the eye and the aperture has a degree of ellipticity that generally balances the amount of astigmatism associated with the eye so that a generally circular image is reflected from the eye.

Abstract: A template set for use in corneal size measurement. The templates take the form of identical thin and flexible blades rounded at one end, and are arranged in a stack in parallel planes. The blades are pivotally coupled together adjacent their opposite ends by a pivot pin which extends through the whole stack. The pivot pin allows individual blades to be pivoted out of the stack for use. Each blade has a circular opening adjacent the rounded end of the blade and the openings are graduated in size in predetermined increments from one end of the stack to the other. Each blade is also visibly marked to indicate the size of the opening.

Abstract: An instrument (20) for measuring the radius of curvature of a cornea (58) of an eye (60) is provided. The instrument (20) includes structure (90, 98, 180) for projecting a reference image (70) onto the cornea (58). The reference image (70) comprises substantially a circle of discontinuous dots (82). A rod (80) of refractile transparent material is provided for optically forming two images (70a, 70b) substantially identical to the reference image (70). Structure (90, 98) is further provided for varying the diameter of the reference image (70) and the two images (70a, 70b) substantially identical to the reference image (70), such that the images form a predetermined image pattern. Structure (36, 38) is provided for measuring the diameter of the reference image (70) when the predetermined image pattern is formed to provide an indication of the radius of curvature of the cornea (58).

Abstract: A hand-held keratoscope designed to project a bright circular ring on the cornea having a circular glass ring attached to a handle by a retainer ring with the circular glass ring having a flat polished top surface and a frosted inward sloping bottom surface.

Abstract: An analysis of the corneal shape through the combination of several keratometer measurements is disclosed. The eye is preferably scanned to a nasal angular position, a central angular position and a temporal angular position. The central position is straight ahead along the patient's line of sight. The temporal and nasal positions are in the broad range of up to 5.degree. to 22.degree.; the intermediate range of 10 to 15.degree.; and the narrow range of 12.degree. to 14.degree. on either side. Measurements in sphere, cylinder and axes are taken. Astigmatism is in the more preferable format of 0.degree.-90.degree. astigmatism and 45.degree.-135.degree. astigmatism. When each individual point is measured with its respective estimate for sphere and cylinder components, these measurements are fitted to an idealized parameter. Then the three sets of curvature measurements taken at the specified locations are reduced to a set of adjusted, idealized curvatures all fitted to an elliptical model.

Abstract: The method of the present invention uses a standard prior art refracting device of the type typically used by an optometrist to refract the human eye in air and in water. Computations utilizing the refraction data obtained during the air and water refraction measurements is used to compute the radius of curvature of the central area of the cornea of a human eye. The method of the present invention thereby substantially facilitates contact lens fitting procedures.