Abstract: Provided herein are methods for objectively determining a visual axis of an eye. An optical axis of a measuring instrument is aligned with an unambiguously determinable axis of the eye which is the pupillary axis crossing the vertex of an anterior surface of a cornea and perpendicular to the vertex. A wave front tilt of radiation of a set of narrow laser beams backscattered from the retina is calculated as a tilt component in a polynomial that describes the wave front. The visual axis is reconstructed from a set of chief rays exiting from the eye after crossing nodal points of the optical system of the eye.

Abstract: Provided are methods for determining an axis of best vision of an eye or for objectively determining a visual axis of an eye and for making the most accurate measurement of refraction. Generally, an optical measuring device or instrument projects laser beams into the eye during a scan. Positions of the projected beams are detected and measured on the retina to produce a set of projections. Wave front tilt of radiation that is backscattered from the retina is calculated as a best fit from the set of projections. The axis of best vision or the visual axis is reconstructed from a set of those traces of chief rays exiting from the eye that cross the nodal point of the optical system of the eye and that are normal to the wave front tilts. Measuring with the Styles Crawford scans centered over this axis provides the most accurate objective refraction.

Abstract: Provided are methods for determining an axis of best vision of an eye or for objectively determining a visual axis of an eye and for making the most accurate measurement of refraction. Generally, an optical measuring device or instrument projects laser beams into the eye during a scan. Positions of the projected beams are detected and measured on the retina to produce a set of projections. Wave front tilt of radiation that is backscattered from the retina is calculated as a best fit from the set of projections. The axis of best vision or the visual axis is reconstructed from a set of those traces of chief rays exiting from the eye that cross the nodal point of the optical system of the eye and that are normal to the wave front tilts. Measuring with the Styles Crawford scans centered over this axis provides the most accurate objective refraction.

Abstract: Provided herein are methods for measuring wave aberrations of the eye. Retinal scattered radiation from a probing laser beam is detected, the wave front tilt is measured as first partial derivatives along known coordinates in a discrete set of the pupil points, the wave front is approximated from this data as functions of the pupil coordinates and the wave aberrations of the eye are thereby calculated. Partial derivatives are determined at any pupil point by spline approximation using the values in a discrete number of points in which the wave front tilts are measured. This set of points may be located along concentric circles or along one of the orthogonal axes. The wave front is reconstructed using numerical integration along the radii with the initial integration point in the center of the pupil. Wave aberrations are calculated from wave front data reconstructed in the form of splines.

Abstract: Eye refraction is measured to achieve desired quality via a selected vision characteristics. A characteristic of vision is selected to correlate to the desired quality of vision from a group of vision characteristics comprising acuity, Strehl ratio, contrast sensitivity, night vision, day vision, and depth of focus, dynamic refraction over a period of time during focus accommodation, and dynamic refraction over a period of time during pupil constriction and dilation. Wavefront aberration measurements are used to objectively measure the state of the eye refraction that defines the desired vision characteristic. The measured state of refraction is expressed with a mathematical function enabling correction of the pre-selected vision characteristic to achieve the desired quality of vision. The mathematical expression function may be a Zernike polynomial having both second order and higher order terms or a function determined by spline mathematical calculations.

Abstract: A method and an instrument is provided for measuring aberration refraction of an eye with a first device for measuring the total aberration refraction of the eye and a second device for measuring the aberration refraction of the cornea of the eye. The component of aberration refraction caused by the lens caused by the lens is calculated using the measured total eye aberration refraction and the measured component of aberration refraction of the cornea mapped over the optical surfaces of the eye. Each component portion of the aberration refraction provides information usable for making appropriate corrective actions at the cornea, at the lens, or both as indicated by the mapped measurements and calculations.

Abstract: The invention relates to medical instrumentation, in particular to diagnostic measuring devices, and can be applied, for example, for high-accuracy vision correction. This method uses probing the eye with a thin laser beam, detecting the radiation scattered by retina, measuring the wave front tilt in the form of first partial derivatives along the coordinates in a discrete set of the pupil points with known coordinates, approximating the wave front from said data as functions of pupil coordinates and calculating the wave aberrations of the eye. Partial derivatives are determined in any point of the pupil by means of spline approximation using the values in a discrete number of points, in which the wave front tilts are measured. This set of points can be located along concentric circles or along one of the orthogonal axes. The wave front is reconstructed using numerical integration along the radii with the initial integration point in the center of the pupil.

Abstract: A method of measuring eye refraction to achieve desired quality according to a selected vision characteristics comprising the steps of selecting a characteristic of vision to correlate to the desired quality of vision from a group of vision characteristics comprising acuity, Strehl ratio, contrast sensitivity, night vision, day vision, and depth of focus, dynamic refraction over a period of time during focus accommodation, and dynamic refraction over a period of time during pupil constriction and dilation; using wavefront aberration measurements to objectively measure the state of the eye refraction that defines the desired vision characteristic; and expressing the measured state of refraction with a mathematical function to enable correction of the pre-selected vision characteristic to achieve the desired quality of vision. The mathematical function of expression may be a Zernike polynomial having both second order and higher order terms or a function determined by spline mathematical calculations.

Abstract: A method and an instrument is provided for measuring aberration refraction of an eye with a first device for measuring the total aberration refraction of the eye and a second device for measuring the aberration refraction of the cornea of the eye. The component of aberration refraction caused by the lens caused by the lens is calculated using the measured total eye aberration refraction and the measured component of aberration refraction of the cornea mapped over the optical surfaces of the eye. Each component portion of the aberration refraction provides information usable for making appropriate corrective actions at the cornea, at the lens, or both as indicated by the mapped measurements and calculations.

Abstract: An instrument for measuring aberration refraction of an eye is provided, having: a lens system defining an instrument optical axis and an alignment device for aligning the visual axis of the eye with the instrument optical axis. A light source produces a probing beam that is projected through the lens system parallel to the instrument optical axis and is selectably positionable partially off-set from the instrument optical axis for entering the eye parallel to the instrument optical axis at a plurality of locations on the cornea of the eye. A first photodetector measures the position of a first portion of the probing beam light scattered back from the retina of the eye to measure aberration refraction of the eye at a plurality of locations. A second photodetector synchronously measures the position of a second portion of the probing beam light reflected back from the cornea of the eye.

Abstract: An instrument for measuring aberration refraction of an eye is provided, having: a lens system defining an instrument optical axis and an alignment device for aligning the visual axis of the eye with the instrument optical axis. A light source produces a probing beam that is projected through the lens system parallel to the instrument optical axis and is selectably positionable partially off-set from the instrument optical axis for entering the eye parallel to the instrument optical axis at a plurality of locations on the cornea of the eye. A first photodetector measures the position of a first portion of the probing beam light scattered back from the retina of the eye to measure aberration refraction of the eye at a plurality of locations. A second photodetector synchronously measures the position of a second portion of the probing beam light reflected back from the cornea of the eye.