Methods and Apparatus for Assessment of Refractive Condition

• US 20160066780A1
• Filed: 04/10/2014
• Published: 03/10/2016
• Est. Priority Date: 04/10/2013
• Status: Active Grant

• Current Assignee: Eyenetra, Inc. A Delaware Corporation
• Original Assignee: Eyenetra, Inc. A Delaware Corporation
• Inventors: Pamplona, Vitor, Raskar, Ramesh
• Granted Patent: US 10,335,027 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 3/0008 provided with illuminating means A61B3/117 takes precedence; goniolenses used for laser treatment A61F9/009; illuminating means for optical instruments G02B27/00
• CPC Class Codes: A61B 3/0025 characterised by electronic signal processing, e.g. eye models
• CPC Class Codes: A61B 3/09 for testing accommodation
• CPC Class Codes: A61B 3/1035 for measuring astigmatism testing astigmatism A61B3/036
• CPC Class Codes: A61B 3/14 Arrangements specially adapted for eye photography apparatus or arrangements for taking photographs per se G03B
• CPC Class Codes: A61B 5/6898 Portable consumer electronic devices, e.g. music players, telephones, tablet computers

Abstract

In exemplary implementations of this invention, an aberrometer is used to measure the refractive condition of any eye. An artificial light source emits light that travels to a light sensor. Along the way, the light enters and then exits the eye, passes through or is reflected from one or more spatial light modulators (SLMs), and passes through an objective lens-system. The SLMs modify a bokeh effect of the imaging system (which is only visible when the system is out-of-focus), creating a blurred version of the SLM patterns. The light sensor then captures one or more out-of-focus images. If there are refractive aberrations in the eye, these aberrations cause the SLM patterns captured in the images to be distorted. By analyzing differences between the distorted captured patterns and the undistorted SLM patterns, refractive aberrations of the eye can be computed and an eyewear measurement generated.

Claims

1. A method of measuring a refractive condition of an eye, which method comprises, in combination:

(a) emitting light from an artificial light source, such that

(i) the light travels along a set of optical paths, which each start at the light source and end at a light sensor, and each enter and then exit the eye,

(ii) the light passes through or is reflected from one or more SLMs, including a first SLM that is optically positioned between the light sensor and the eye, and

(iii) the light passes through an objective lens-system that is optically between the eye and the light sensor;

(b) using the light sensor to capture one or more images; and

(c) using one or more processors

(i) to determine differences between a first visual pattern and a second visual pattern, the first visual pattern being based at least in part on a pattern that appears in at least one of the images, and the second visual pattern being based at least in part on a pattern displayed by the first SLM, and

(ii) to compute the refractive condition, based at least in part on the differences;

wherein (1) the light sensor and each and every optical element that is optically between the light sensor and the eye together comprise a camera, and (2) the camera is not focused on the first SLM and is not focused on the retina of the eye.

2. The method of claim 1, wherein a second SLM is optically positioned between the light source and the eye.

3. The method of claim 2, wherein:

(a) the light passes through a second lens system that is optically between the light source and the eye and is optically in front of the second SLM; and

(b) the second lens system has an optical power that prevents the eye from focusing on the second SLM and from focusing on the light source.

4. The method of claim 1, wherein the objective lens-system, the light sensors, and the one or more processors are housed in a mobile computing device.

5. The method of claim 4, wherein the first SLM is housed in a device that is releasably attached to the mobile computing device.

6. The method of claim 1, wherein the refractive condition is myopia, hyperopia or astigmatism.

7. The method of claim 1 wherein the refractive condition is keratoconus, optical coma, trefoil or another high-order refractive aberration.

8. A method of measuring a refractive condition of an eye, which method comprises, in combination:

(a) emitting light from an artificial light source, such that

(i) the light travels along a set of optical paths, which each start at the light source and end at a light sensor, and each enter and then exit the eye,

(ii) the light passes through or is reflected from one or more SLMs, including a first SLM that is optically positioned between the light source and the eye, and

(iii) the light passes through a first lens system that is optically between the light source and the eye and that is optically in front of the first SLM;

(b) using the light sensor to capture one or more images; and

(c) using one or more processors

(i) to determine distortion of a first visual pattern relative to a second visual pattern, the first visual pattern being based at least in part on a pattern that appears in at least one of the images, and the second visual pattern being based at least in part on a pattern displayed by the first SLM, and

(ii) to compute the refractive condition, based at least in part on the distortion;

wherein the optical power of the first lens system is such that the eye cannot focus on the first SLM and cannot focus on the light source.

9. The method of claim 8, wherein an objective lens-system is optically between the eye and the light sensor.

10. The method of claim 9, wherein:

(a) the objective lens-system, the light sensor and the one or more processors are housed in a mobile computing device; and

(b) the first SLM is housed in a device that is releasably attached to the mobile computing device.

11. The method of claim 8, wherein the refractive condition is myopia, hyperopia or astigmatism.

12. The method of claim 8, wherein the light passes through more than one SLM.

13. A method of measuring refractive condition of an eye, which method comprises, in combination:

(a) emitting light from an artificial light source, such that at least part of the light

(i) travels along a set of optical paths that each start at the light source and end at a light sensor, and each enter and then exit the eye,

(iii) passes through or is reflected from one or more SLMs, including a first SLM, and

(iv) passes through an objective lens-system that is optically between the eye and the light sensor;

(b) using the light sensor to capture one or more images; and

(c) using one or more processors

(i) to determine differences between a first visual pattern and a second visual pattern, the first visual pattern being based at least in part on a pattern that appears in at least one of the images, and the second visual pattern being based at least in part on a pattern displayed by the first SLM, and

(ii) to compute the refractive condition, based at least in part on the differences.

14. The method of claim 13, wherein the first SLM is optically positioned between the light sensor and the eye.

15. Apparatus comprising, in combination:

(a) an SLM, and

(b) a structure that

(i) houses and mechanically supports the SLM, and

(ii) is configured to be releasably attached to a mobile computing device, which mobile computing device is configured to take a photograph of an eye of a human when (A) the attachment is pressed against the human, (B) the camera is not focused on the SLM,

(C) the camera is not focused on the retina of the eye, and (D) the light being captured in the photograph has passed through the SLM.

16. The apparatus of claim 15, wherein the apparatus further comprises a light source for emitting collimated light.

17. The apparatus of claim 15, wherein the structure is configured to keep the SLM at a distance from the eye when the structure is pressed against a region of the user'"'"'s face.

18. The apparatus of claim 15, wherein the SLM is configured to display a light attenuation pattern that does not vary over time.

19. The apparatus of claim 15, wherein the SLM is configured to display a light attenuation pattern that varies over time.

20. The apparatus of claim 15, wherein the SLM includes color filters, polarizing filters and optical coatings.