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: Two stages of ray tracing aberrometry include preliminary stage of measurement with probing beams successively entering the eye in parallel to the optical axis and the main stage of measurement with probing beams successively entering the same points of the eye but tilted in the way to compensate for the refraction variations over the entrance aperture measured in the preliminary stage. The main stage of measurement may be implemented in the combination of units, one compensating for defocus another—compensating for higher order aberrations. In one embodiment, the probing channel contains two two-coordinate acousto-optic deflectors with a collimating lens between them. The procedure of main stage of measurement may be iteratively repeated until the wave front conjugation is achieved with a prescribed accuracy.

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: An apparatus and method for measuring refractive characteristics of human eyes with an objective refraction measuring device for measuring refraction in at least one eye, the objective refraction measuring system having a proximal end and a distal end, the objective refraction measuring system suitable for looking in the proximal end and seeing out the distal end; an open field visual target. An open viewing lane is provided between the eye and the open field visual target, the viewing lane has sufficient length to allow for focusing the eye at infinity and for natural accommodation at true distance targets, such near distances such as reading distances. The objective refraction measuring device can be positioned in the viewing lane to measure the eye while the eye is focused on the open field visual target.

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: 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 apparatus and method for measuring refractive characteristics of human eyes with an objective refraction measuring device for measuring refraction in at least one eye, the objective refraction measuring system having a proximal end and a distal end, the objective refraction measuring system suitable for looking in the proximal end and seeing out the distal end; an open field visual target. An open viewing lane is provided between the eye and the open field visual target, the viewing lane has sufficient length to allow for focusing the eye at infinity and for natural accommodation at true distance targets, such near distances such as reading distances. The objective refraction measuring device can be positioned in the viewing lane to measure the eye while the eye is focused on the open field visual target.

Abstract: Measurement of wave abberations of eye is performed by probing the eye with a narrow beam of laser radiation and measuring the wave front tilts in subapertures of radiation, exiting back from the eye, by of a Hartman-Shack sensor. In the process of measurements, dosed tilts are introduced into the wave, repeated several times with varied tilts of the beam as a whole during each subsequent measurement, and the reconstruction of the wave front is performed in accordance with the data obtained in all angular positions of the beam. The device for measurement includes a probing channel, a measuring channel and a channel of positioning. For controlling the wave front, a unit of dosed tilting of the wave front is introduced, based on the acousto-optic deflector, in the first embodiment—in the measuring channel, and in the second embodiment—in the probing channel. A wider dynamic range of measured wave aberrations of the human eye is achieved.

Abstract: The invention relates to a method and to a device for completely correcting visual defects of the human eye. The invention mentions combinations of measuring and treatment methods that allow the complete correction of defects of the human eye if applied according to the invention. Measuring methods are used that precisely detect the surface of the cornea and that also register the aberrations that occur in the beam path up to the retina. The computer-assisted evaluation of these measurement results combined with the calculation of optimally corrected lenses (for example after a cataract operation) or of optimally correcting cornea surfaces makes it possible to produce a patient-specific lens and/or to shape the retina so that it optimally corrects the aberration. To this end, the invention preferably uses a spot scanning excimer laser system and makes use of the topography of the eye.

Abstract: Measurement of wave abberations of eye is performed by probing the eye with a narrow beam of laser radiation and measuring the wave front tilts in subapertures of radiation, exiting back from the eye, by of a Hartman-Shack sensor. In the process of measurements, dosed tilts are introduced into the wave, repeated several times with varied tilts of the beam as a whole during each subsequent measurement, and the reconstruction of the wave front is performed in accordance with the data obtained in all angular positions of the beam. The device for measurement includes a probing channel, a measuring channel and a channel of positioning. For controlling the wave front, a unit of dosed tilting of the wave front is introduced, based on the acousto-optic deflector, in the first embodiment—in the measuring channel, and in the second embodiment—in the probing channel. A wider dynamic range of measured wave aberrations of the human eye is achieved.

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.