CN-115397307-B - System and method for identifying a person's visual axis

CN115397307BCN 115397307 BCN115397307 BCN 115397307BCN-115397307-B

Abstract

The present disclosure relates generally to methods and apparatus for accurately identifying the visual axis of an eye. In one embodiment, the visual axis recognition system includes a fixed light source, a camera, a processing system, and a multifocal lens. The patient passes his line of sight through the multifocal lens and focuses onto a fixed light beam provided by a fixed light source. The fixed beam of light passes through the multifocal lens creating two or more images on or near the patient's retina. The multifocal lens and/or the patient's eyes are then moved relative to each other while the patient continues to maintain his line of sight on the fixed beam. When the centers of the multiple images are coincident on the retina, the patient's visual axis may be positioned by determining the position of the optical center of the multifocal trial lens relative to the patient's eye.

Inventors

Z. Bauer

Assignees

爱尔康公司
爱尔康公司

Dates

Publication Date: 20260421
Application Date: 20210408
Priority Date: 20210408

Claims (15)

1. A method for determining a position of a visual axis of an eye of a patient, the method comprising: Placing a multifocal optical lens near an eye of the patient, the multifocal optical lens comprising two or more optical powers having corresponding spatially coincident optical centers at an optical center of the multifocal optical lens, wherein, when a visual axis recognition system is used, the multifocal optical lens is coupled to a non-patient device comprising an ophthalmic testing device; Generating and directing a fixation light toward an eye of the patient, the fixation light forming two or more images at a focal point near a retina of the eye of the patient, the two or more images corresponding to two or more optical powers of the multifocal optical lens; capturing an image of the patient's eye and the multifocal optical lens along the direction of the fixation light; determining an X/Y position of the patient's eye relative to an X/Y position of an optical center of the multifocal optical lens; Moving the multifocal optical lens by displacing the multifocal optical lens relative to the patient's eye by movement of the non-patient device while the patient maintains its line of sight on the fixation light until centers of the two or more images coincide in the patient's field of view, and A position of a visual axis of the patient's eye at a pupil plane of the patient's eye is identified, the position of the visual axis corresponding to a position of an optical center of the multifocal optical lens as viewed from the direction of the fixation light.
2. The method of claim 1, wherein the multifocal optical lens includes an optical coating on two or more surfaces thereof.
3. The method of claim 2, wherein the multifocal optical lens is configured to form more than two focal points within the patient's eye.
4. The method of claim 1, wherein the position of the visual axis further corresponds to the position of the optical center of the multifocal optical lens when the centers of the two or more images coincide with each other in the patient's field of view.
5. The method of claim 1, wherein the fixed light is spectrally separated by the multifocal optical lens into two or more wavelength ranges having different refractive index and reflectivity characteristics.
6. The method of claim 1, wherein an optical center of the multifocal optical lens is marked by a reticle mark.
7. The method of claim 1, wherein identifying the position of the visual axis of the patient's eye further comprises: During a period of time when the patient maintains his line of sight on the fixation light, the X/Y positions of the optical center of the multifocal optical lens relative to the position of the patient's eyes are spatially averaged so that the patient sees a coincident image formed by the fixation light.
8. The method of claim 7, wherein the period of time is between about 5 seconds and about 60 seconds.
9. The method of claim 1, wherein the multifocal optical lens is a compound diffractive optical element configured to form an ultralong focal line.
10. The method of claim 9, wherein the multifocal optical lens comprises an axicon.
11. The method of claim 9, wherein the multifocal optical lens comprises an aspherically extended depth of focus lens.
12. A system for determining a position of a visual axis of an eye of a patient, the system comprising: A multifocal optical lens comprising two or more optical powers having corresponding spatially coincident optical centers at an optical center of the multifocal optical lens, and coupled to a patient device or to a non-patient device, the patient device and the non-patient device configured to provide displacement of the multifocal optical lens relative to an eye of the patient; A fixed light source for generating and directing a fixed light toward the patient's eye, the fixed light forming two or more images at a focal point near the patient's eye retina, the two or more images corresponding to two or more optical powers of the multifocal optical lens; A detector configured to track movement of the eye, the detector further configured to capture an image of the multifocal optical lens relative to a position of the eye, and A processing system configured to identify a location of a visual axis of the eye at an anterior surface of the eye based on the image captured by the detector, wherein the visual axis of the eye corresponds to an optical center of the multifocal optical lens when centers of two or more foci of the multifocal optical lens coincide in a field of view of the patient and form an overlapping image.
13. The system of claim 12, wherein the multifocal optical lens is a compound diffractive optical element configured to form an ultralong focal line.
14. The system of claim 13, wherein the multifocal optical lens comprises an aspherically extended depth of focus lens.
15. The system of claim 12, wherein the processing system being configured to identify the location of the visual axis of the eye comprises the processing system being configured to: During a period of time when a patient maintains his line of sight on a fixation light, the X/Y position of the optical center of the multifocal optical lens relative to the position of the eye is averaged so that the patient sees an overlapping image formed by the fixation light.

Description

System and method for identifying a person's visual axis Background Technical Field Embodiments of the present disclosure relate generally to methods and apparatus for visual characteristics, and more particularly, to methods and apparatus for accurately identifying the visual axis of an eye. Background Conventional presbyopia treatment techniques typically involve determining the relative position of the visual axis of each eye of the patient. Accurate determination of these axes is critical for effective placement of small area bifocal, multifocal, and extended depth of focus (EDOF) intraocular lenses (IOLs). Even if the lenses are slightly misaligned, any of the benefits expected from surgically implanting the lenses may be severely hampered. Other examples of presbyopia treatments that may also benefit from visual axis determination include LASIK, presbyLASIK or multifocal LASIK, and refractive keratomileusis (PRK) procedures, to name a few. The visual axis is the actual line of sight of a person, which is a straight line connecting the fovea of the eye (the small depression in the retina and the sharpest point of view) and a fixed point in the patient's field of view. Measuring the visual axis is therefore crucial for determining the placement of bifocal and multifocal lenses, since the viewing area of such lenses is narrow and even slight misalignments can severely hamper their function. Currently, there is no diagnostic device for accurately and precisely determining the position of the visual axis. Instead, the position of the visual axis is generally approximately midway between the optical axis and the corneal vertex, or a first Purkinje image, which is a reflection of the fixed light on the outer surface of the cornea. This approach is often inaccurate because the visual axis may be located far from the above-mentioned intermediate point (e.g., especially in a damaged or irregularly shaped eye). Accordingly, there is a need in the art for improved methods and apparatus for identifying the visual axis of an eye. Disclosure of Invention The present disclosure relates generally to methods and apparatus for accurately identifying the visual axis of an eye. In certain embodiments, a method for determining a position of a visual axis of an eye of a patient is provided. The method includes placing a multifocal optical lens near an eye of the patient, wherein the multifocal optical lens includes two or more optical powers with corresponding and spatially coincident optical centers at an optical center of the multifocal optical lens. A fixed beam of light is generated and directed toward the patient's eye, forming two or more images corresponding to two or more optical powers of the multifocal lens near the patient's retina. The method further includes capturing an image of the patient's eye and the optical lens along the direction of the fixed beam and determining an X/Y position of the patient's eye relative to an X/Y position of an optical center of the multifocal optical lens. The multifocal optical lens is moved in the X/Y direction while the patient maintains its line of sight on the fixed light until the centers of the two or more images coincide in the patient's field of view. At this time, the position of the visual axis of the patient's eye, which corresponds to the position of the optical center of the multifocal optical lens as seen from the direction of the fixed light beam, is detected and positioned at the pupil plane of the patient's eye. Drawings So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. Fig. 1 shows a cross-sectional top view of a human eye. Fig. 2A illustrates a schematic diagram of a visual axis recognition system in accordance with certain embodiments of the present disclosure. Fig. 2B illustrates a schematic diagram of an exemplary optical element for a visual axis recognition system, in accordance with certain embodiments of the present disclosure. Fig. 3A illustrates a schematic diagram of a portion of a visual axis recognition system in accordance with certain embodiments of the present disclosure. Fig. 3B illustrates a schematic diagram of a portion of a visual axis recognition system in accordance with certain embodiments of the present disclosure. Fig. 4A illustrates a schematic top view of a portion of a visual axis recognition system in accordance with certain embodiments of the present disclosure. Fig. 4B illustrates a schematic top view of a portion of a visual axis recognition system in accordance with certain embodimen