Abstract: Embodiments of the invention include a method to determine a binocular alignment, the method comprising: measuring a disassociated phoria of a first eye and a second eye of a patient at an apparent distance; and determining an accommodative convergence of the first eye and the second eye at the apparent distance using the measured disassociated phoria. In other embodiments, a system to determine a binocular alignment comprises a stereo display, for a projection of images for a first eye and a second eye; an accommodation optics, to modify the projection of the images according to an apparent distance; an eye tracker, to track an orientation of the first eye and the second eye; and a computer, coupled to the stereo display, the accommodation optics and the eye tracker, to manage a determination of the binocular alignment.

Abstract: A method to determine a binocular alignment includes measuring a disassociated phoria of a patient at a first simulated distance by presenting fusible images including targets with a first parallax corresponding to the first simulated distance, using a headset stereo display at a screen distance; presenting non-fusible images by presenting the target for a first eye with the first parallax and presenting a disassociated targetless image for a second eye, and measuring the disassociated phoria in response to the presenting of non-fusible images, using an eye tracker of the headset; and determining a vergence of the patient at the first simulated distance by presenting fusible images for the first and second eyes with the first parallax, corrected with the measured disassociated phoria; measuring an associated phoria in response to the presenting of fusible images; and determining the vergence as a combination of the disassociated phoria and the associated phoria.

Abstract: Embodiments of the invention include a method to determine a binocular alignment, the method comprising: measuring a disassociated phoria of a first eye and a second eye of a patient at an apparent distance; and determining an accommodative convergence of the first eye and the second eye at the apparent distance using the measured disassociated phoria. In other embodiments, a system to determine a binocular alignment comprises a stereo display, for a projection of images for a first eye and a second eye; an accommodation optics, to modify the projection of the images according to an apparent distance; an eye tracker, to track an orientation of the first eye and the second eye; and a computer, coupled to the stereo display, the accommodation optics and the eye tracker, to manage a determination of the binocular alignment.

Abstract: Embodiments of the invention include a method to determine a binocular alignment, the method comprising: measuring a disassociated phoria of a first eye and a second eye of a patient at an apparent distance; and determining an accommodative convergence of the first eye and the second eye at the apparent distance using the measured disassociated phoria. In other embodiments, a system to determine a binocular alignment comprises a stereo display, for a projection of images for a first eye and a second eye; an accommodation optics, to modify the projection of the images according to an apparent distance; an eye tracker, to track an orientation of the first eye and the second eye; and a computer, coupled to the stereo display, the accommodation optics and the eye tracker, to manage a determination of the binocular alignment.

Abstract: An eye-strain reducing lens is characterized by an x-y-z coordinate system, and includes a distance-vision region, having a negative distance-vision optical power, configured to refract a light ray, directed by a source at a distance-vision region point at a distance-vision x-distance from a center of the coordinate system, to propagate to an eye-center-representative location; and a near-vision region, having a near-vision optical power that matches the distance-vision optical power within 0.5 D, configured to refract a light ray, directed by the source at a near-vision region point at a near-vision x-distance from the center of the coordinate system, to propagate to an x-z location of the eye-center representative location at a corresponding y height; wherein the near-vision x-distance is smaller than the distance-vision x-distance.

Abstract: A class of prismatic contact lenses includes a first prism zone, having a first prism and a first optical power; and a progressive prism zone, adjacent to the first prism zone, having a progressive prism that varies from the first prism to a second prism. The prismatic contact lens can further comprise a second prism zone, adjacent to the progressive prism zone, having the second prism and a second optical power. Another class of prismatic contact lenses include a first prism zone, having a first prism and a first optical power; a second prism zone, adjacent to the first prism zone, having a second prism and a second optical power; and a sharp transition between the first prism zone and the second prism zone.

Abstract: Embodiments of the invention include a method to determine a binocular alignment, the method comprising: measuring a disassociated phoria of a first eye and a second eye of a patient at an apparent distance; and determining an accommodative convergence of the first eye and the second eye at the apparent distance using the measured disassociated phoria. In other embodiments, a system to determine a binocular alignment comprises a stereo display, for a projection of images for a first eye and a second eye; an accommodation optics, to modify the projection of the images according to an apparent distance; an eye tracker, to track an orientation of the first eye and the second eye; and a computer, coupled to the stereo display, the accommodation optics and the eye tracker, to manage a determination of the binocular alignment.

Abstract: A system to determine a binocular alignment, comprises a first optical unit, including a first display, to display images for a first eye, actuatable along a longitudinal direction according to a simulated distance and an optical power of the first eye, and a first eye tracker assembly, to track a gaze direction of the first eye, adjustable in a horizontal lateral direction to accommodate a pupillary distance of the first eye; and a second optical unit, including a second display, to display images for a second eye, actuatable along the longitudinal direction according to a simulated distance and an optical power of the second eye, and a second eye tracker assembly, to track a gaze direction of the second eye, adjustable in the horizontal lateral direction to accommodate a pupillary distance of the second eye; and a computer, to determine the binocular alignment based on the gaze directions.

Abstract: Embodiments of the invention include a method to determine a binocular alignment, the method comprising: measuring a disassociated phoria of a first eye and a second eye of a patient at an apparent distance; and determining an accommodative convergence of the first eye and the second eye at the apparent distance using the measured disassociated phoria. In other embodiments, a system to determine a binocular alignment comprises a stereo display, for a projection of images for a first eye and a second eye; an accommodation optics, to modify the projection of the images according to an apparent distance; an eye tracker, to track an orientation of the first eye and the second eye; and a computer, coupled to the stereo display, the accommodation optics and the eye tracker, to manage a determination of the binocular alignment.

Abstract: A convergence-reducing lens, wherein a central normal of the convergence-reducing lens defines a z-axis, and a center of the convergence-reducing lens defines a tangential, centered x-y plane, together defining a coordinate system, the convergence-reducing lens comprising a distance-vision region, having a negative distance-vision optical power, to refract a light ray, directed parallel to the z-axis at a distance-vision region point at an x-distance from a y-z plane of the coordinate system, so that its extension intersects the y-z plane at a distance-vision intersection z-distance; and a near-vision region, having a near-vision optical power that matches the distance-vision optical power within 0.

Abstract: A convergence-reducing lens, wherein a central normal defines a z-axis, and a central region defines an x-y plane, together defining an x-y-z coordinate system, the convergence-reducing lens comprising a distance-vision region with a negative distance-vision optical power, having a distance-vision front surface with a center of distance-vision front curvature, and a distance-vision rear surface with a center of distance-vision rear curvature; and a near-vision region with an optical power within 0.

Abstract: Embodiments of the invention include a method to determine a binocular alignment, the method comprising: measuring a disassociated phoria of a first eye and a second eye of a patient at an apparent distance; and determining an accommodative convergence of the first eye and the second eye at the apparent distance using the measured disassociated phoria. In other embodiments, a system to determine a binocular alignment comprises a stereo display, for a projection of images for a first eye and a second eye; an accommodation optics, to modify the projection of the images according to an apparent distance; an eye tracker, to track an orientation of the first eye and the second eye; and a computer, coupled to the stereo display, the accommodation optics and the eye tracker, to manage a determination of the binocular alignment.

Abstract: An eye-strain reducing lens is characterized by an x-y-z coordinate system, and includes a distance-vision region, having a negative distance-vision optical power, configured to refract a light ray, directed by a source at a distance-vision region point at a distance-vision x-distance from a center of the coordinate system, to propagate to an eye-center-representative location; and a near-vision region, having a near-vision optical power that matches the distance-vision optical power within 0.5 D, configured to refract a light ray, directed by the source at a near-vision region point at a near-vision x-distance from the center of the coordinate system, to propagate to an x-z location of the eye-center representative location at a corresponding y height; wherein the near-vision x-distance is smaller than the distance-vision x-distance.

Abstract: A convergence-reducing lens, wherein a central normal of the convergence-reducing lens defines a z-axis, and a center of the convergence-reducing lens defines a tangential, centered x-y plane, together defining a coordinate system, the convergence-reducing lens comprising a distance-vision region, having a negative distance-vision optical power, to refract a light ray, directed parallel to the z-axis at a distance-vision region point at an x-distance from a y-z plane of the coordinate system, so that its extension intersects the y-z plane at a distance-vision intersection z-distance; and a near-vision region, having a near-vision optical power that matches the distance-vision optical power within 0.5D.

Abstract: A convergence-reducing lens, wherein a central normal defines a z-axis, and a central region defines an x-y plane, together defining an x-y-z coordinate system, the convergence-reducing lens comprising a distance-vision region with a negative distance-vision optical power, having a distance-vision front surface with a center of distance-vision front curvature, and a distance-vision rear surface with a center of distance-vision rear curvature; and a near-vision region with an optical power within 0.

Abstract: An off-axis curvature center lens is characterized by an x-y-z coordinate system of the convergence-reducing lens, the off-axis curvature lens comprising a distance-vision region with a non-negative distance-vision optical power, having a front distance-vision surface with a center of front distance-vision curvature, and a rear distance-vision surface with a center of rear distance-vision curvature; and a near-vision region with an optical power within 0.5D of the distance-vision optical power, having a front near-vision surface with a center of front near-vision curvature, and a rear near-vision surface with a center of rear near-vision curvature; wherein at least one of an x-coordinate of the center of front near-vision curvature is nasal relative to an x-coordinate of the center of front distance-vision curvature, and an x-coordinate of the center of rear near-vision curvature is temporal relative to an x-coordinate of the center of rear distance-vision curvature.

Abstract: Embodiments of the invention include a method to determine a binocular alignment, the method comprising: measuring a disassociated phoria of a first eye and a second eye of a patient at an apparent distance; and determining an accommodative convergence of the first eye and the second eye at the apparent distance using the measured disassociated phoria. In other embodiments, a system to determine a binocular alignment comprises a stereo display, for a projection of images for a first eye and a second eye; an accommodation optics, to modify the projection of the images according to an apparent distance; an eye tracker, to track an orientation of the first eye and the second eye; and a computer, coupled to the stereo display, the accommodation optics and the eye tracker, to manage a determination of the binocular alignment.

Abstract: An eye-strain reducing lens is characterized by an x-y-z coordinate system, and includes a distance-vision region, baying a non-negative distance-vision optical power, configured to refract a light ray, directed by a source at a distance-vision region point at a distance-vision x-distance from a center of the coordinate system, to propagate to an eye-center-representative location; and a near-vision region, having a near-vision optical power that matches the distance-vision optical point within 0.5 D, configured to refract a light ray, directed by the source at a near-vision region point at a near-vision x-distance from the center of the coordinate system, to propagate to the same eye-center representative location; wherein the near-vision x-distance is smaller than the distance -vision x-distance.

Abstract: A convergence-reducing lens of a low-convergence spectacle is characterized by a central normal of the convergence-reducing lens that defines a z-axis, and a center of the convergence-reducing lens defines a tangential, centered x-y plane, together defining an x-y-z coordinate system, the convergence-reducing lens comprising a distance-vision region, having a non-negative distance-vision optical power, configured to refract a light ray, directed parallel to the z-axis at a distance-vision region point at an x-distance from a y-z plane of the coordinate system, to intersect the y-z-plane at a distance-vision intersection z-distance; and a near-vision region, having a near-vision optical power that matches the distance-vision optical power within 0.

Abstract: A class of prismatic contact lenses includes a first prism zone, having a first prism and a first optical power; and a progressive prism zone, adjacent to the first prism zone, having a progressive prism that varies from the first prism to a second prism. The prismatic contact lens can further comprise a second prism zone, adjacent to the progressive prism zone, having the second prism and a second optical power. Another class of prismatic contact lenses include a first prism zone, having a first prism and a first optical power; a second prism zone, adjacent to the first prism zone, having a second prism and a second optical power; and a sharp transition between the first prism zone and the second prism zone.