# US 10,117,575 B2 · Method and apparatus for fixation measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,117,575 B2 - Document ID: US10117575B2 - Status: Granted - Kind: B2 - Application number: 14/806,593 - Filed: 2015-07-22 - Published: 2016-01-28 - Granted: 2018-11-06 - Earliest claimed: 2014-07-24 - Assignees: Rebiscan, Inc. - Applicants: REBIScan, Inc. - Inventors: Robert Scott Winsor - Web page: https://patentgrep.com/patent/US10117575B2 ## CPC - A61B 3/113: for determining or recording eye movement - G02B 19/0028: {refractive and reflective surfaces, e.g. non-imaging catadioptric systems} - G02B 26/105: {with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence)} - G02B 26/106: {having diffraction gratings as scanning elements, e.g. holographic scanners (holographic optical elements G02B5/32, holography G03H)} - G02B 27/4233: {having a diffractive element [DOE] contributing to a non-imaging application (diffusers having a diffractive element G02B5/0252; filters having a diffractive element G02B5/203; systems for controlling the direction of light having diffractive elements G02B26/0808; scanning systems having diffractive elements G02B26/106; beam shaping systems using diffractive optical elements G02B27/0944; beam splitting or combining systems operating by diffraction G02B27/1086)} - A61B 3/0025: {characterised by electronic signal processing, e.g. eye models} - G02B 27/283: {used for beam splitting or combining} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A method and apparatus for fixation measurement includes rotating a first reflector comprising a diffraction component about a rotation axis, the first reflector being configured to reflect light received from a light source onto a second reflector via the diffraction component and reflect light received from the second reflector via the diffraction component and capturing light which is reflected by the second reflector and subsequently reflected by the first reflector with one or more photodetectors. ## Claims ### Claim 1 An apparatus for fixation measurement, the apparatus comprising: a first reflector comprising a diffraction component, wherein the first reflector is configured to rotate about a rotation axis, reflect light received from a light source onto a second reflector via the diffraction component, and reflect light received from the second reflector via the diffraction component; and one or more photodetectors configured to capture light which is reflected by the second reflector and subsequently reflected by the first reflector; wherein a combination of a reflective component in the first reflector and the diffractive component in the first reflector is configured to rotate and re-image a waist of the light received from the light source onto the second reflector without inducing torque. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the second reflector is configured to reflect light received from the first reflector onto a target area adapted to receive one or more eyes of a patient and to reflect light reflected from the one or more eyes of the patient onto the first reflector. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the light reflected from the one or more eyes of the patient is reflected from one or more retinas of the one or more eyes and wherein the one or more photodetectors are configured to capture the light reflected from one or more retinas of the one or more eyes of the patient via the second reflector and the first reflector as light data and wherein the light data includes information indicating fixation of the one or more eyes. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein the fixation of the one or more eyes is calculated based on one or more polarization-related changes between light emitted by the light source and the light reflected from the one or more retinas of the one or more eyes of the patient. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein a center of mass of the first reflector lies on the rotation axis. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the diffraction component comprises one of: a diffraction grating superimposed on a concave mirror, a concave Fresnel mirror, a reflection diffraction grating disposed adjacent to a lens, and a wedge prism disposed adjacent to a concave mirror. ### Claim 7 (depends on 1) The apparatus of claim 1, further comprising one or more beam splitters disposed between the one or more photodetectors and the first reflector. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the one or more beam splitters include a polarization beam splitter. ### Claim 9 A method for fixation measurement, the method comprising: rotating a first reflector comprising a diffraction component about a rotation axis, wherein the first reflector is configured to reflect light received from a light source onto a second reflector via the diffraction component and reflect light received from the second reflector via the diffraction component; and capturing light which is reflected by the second reflector and subsequently reflected by the first reflector with one or more photodetectors; wherein a combination of a reflective component in the first reflector and the diffractive component in the first reflector is configured to rotate and re-image a waist of the light received from the light source onto the second reflector without inducing torque. ### Claim 10 (depends on 9) The method of claim 9, wherein the second reflector is configured to reflect light received from the first reflector onto a target area adapted to receive one or more eyes of a patient and to reflect light reflected from the one or more eyes of the patient onto the first reflector. ### Claim 11 (depends on 10) The method of claim 10, wherein the light reflected from the one or more eyes of the patient is reflected from one or more retinas of the one or more eyes and wherein the one or more photodetectors are configured to capture the light reflected from one or more retinas of the one or more eyes of the patient via the second reflector and the first reflector as light data and wherein the light data includes information indicating fixation of the one or more eyes. ### Claim 12 (depends on 11) The method of claim 11, wherein the fixation of the one or more eyes is calculated based on one or more polarization-related changes between light emitted by the light source and the light reflected from the one or more retinas of the one or more eyes of the patient. ### Claim 13 (depends on 9) The method of claim 9, wherein a center of mass of the first reflector lies on the rotation axis. ### Claim 14 (depends on 9) The method of claim 9, wherein the diffraction component comprises one of: a diffraction grating superimposed on a concave mirror, a concave Fresnel mirror, a reflection diffraction grating disposed adjacent to a lens, and a wedge prism disposed adjacent to a concave mirror. ### Claim 15 (depends on 9) The method of claim 9, wherein the light which is reflected by the second reflector and subsequently reflected by the first reflector passes through one or more beam splitters disposed between the one or more photodetectors and the first reflector prior to capture by the one or more photodetectors. ### Claim 16 (depends on 15) The method of claim 15, wherein the one or more beam splitters include a polarization beam splitter. ### Claim 17 (depends on 1) The apparatus of claim 1, wherein the waist is re-imaged to an area on the second reflector that is dependent on a degree of rotation of the first reflector about the rotation axis and wherein a full rotation of the first reflector about the rotation axis results in the waist being re-imaged to a plurality of areas on the second reflector, the plurality of areas forming a circle. ### Claim 18 (depends on 3) The apparatus of claim 3, wherein the light data includes information indicating fixation of two eyes of the patient and wherein a misalignment in the fixation of the two eyes corresponds to strabismus. ### Claim 19 (depends on 9) The method of claim 9, wherein the waist is re-imaged to an area on the second reflector that is dependent on a degree of rotation of the first reflector about the rotation axis and wherein a full rotation of the first reflector about the rotation axis results in the waist being re-imaged to a plurality of areas on the second reflector, the plurality of areas forming a circle. ### Claim 20 (depends on 11) The method of claim 11, wherein the light data includes information indicating fixation of two eyes of the patient and wherein a misalignment in the fixation of the two eyes corresponds to strabismus.