Augmented reality pulse oximetry
One embodiment is directed to a system comprising a head-mounted member removably coupleable to the user's head; one or more electromagnetic radiation emitters coupled to the head-mounted member and configured to emit light with at least two different wavelengths toward at least one of the eyes of the user; one or more electromagnetic radiation detectors coupled to the head-mounted member and configured to receive light reflected after encountering at least one blood vessel of the eye; and a controller operatively coupled to the one or more electromagnetic radiation emitters and detectors and configured to cause the one or more electromagnetic radiation emitters to emit pulses of light while also causing the one or more electromagnetic radiation detectors to detect levels of light absorption related to the emitted pulses of light, and to produce an output that is proportional to an oxygen saturation level in the blood vessel.
1. A method of determining oxygen saturation of a user, comprising:
a. removably coupling a head-mounted member to a head of the user;
b. emitting, with one or more electromagnetic radiation emitters coupled to the head-mounted member, light with at least two different wavelengths in the visible to infrared spectrum in a direction of at least one eye of the user and having an associated field of irradiation that includes a retina and a sclera of the eye of the user;
c. receiving, with one or more electromagnetic radiation detectors coupled to the head-mounted member, light reflected after encountering at least one blood vessel of the retina or the sclera of the eye of the user; and
d. activating a controller, operatively coupled to the one or more electromagnetic radiation emitters and one or more electromagnetic radiation detectors, to cause the one or more electromagnetic radiation emitters to emit pulses of light while also causing the one or more electromagnetic radiation detectors to detect levels of light absorption related to the pulses of light, and to produce an output that is proportional to an oxygen saturation level in the blood vessel by determining a ratio of light having the second wavelength divided by light having the first wavelength detected by the one or more electromagnetic radiation detectors.
2. The method of claim 1 , wherein the head-mounted member comprises an eyeglasses frame.
3. The method of claim 2 , wherein the eyeglasses frame is a binocular eyeglasses frame.
4. The method of claim 1 , wherein the one or more radiation emitters comprises a light emitting diode.
5. The method of claim 4 , wherein the one or more radiation emitters comprises a plurality of light emitting diodes configured to emit electromagnetic radiation at two predetermined wavelengths.
6. The method of claim 5 , wherein the plurality of light emitting diodes are configured to emit electromagnetic radiation at a first wavelength of about 660 nanometers, and a second wavelength of about 940 nanometers.
7. The method of claim 5 , wherein the one or more radiation emitters are configured to emit electromagnetic radiation at the two predetermined wavelengths sequentially.
8. The method of claim 5 , wherein the one or more radiation emitters are configured to emit electromagnetic radiation at the two predetermined wavelengths simultaneously.
9. The method of claim 1 , wherein the one or more electromagnetic radiation detectors comprises a device selected from the group consisting of: a photodiode, a photodetector, and a digital camera sensor.
10. The method of claim 1 , wherein the controller causes the plurality of electromagnetic radiation emitters to emit a cyclic pattern of first wavelength on, then second wavelength on, then both wavelengths off, such that the one or more electromagnetic radiation detectors detect the first and second wavelengths separately.
11. The method of claim 10 , wherein the controller is configured to cause the plurality of electromagnetic radiation emitters to emit a cyclic pattern of first wavelength on, then second wavelength on, then both wavelengths off, in a cyclic pulsing pattern about thirty times per second.
12. The method of claim 1 , wherein the ratio is converted to an oxygen saturation reading via a lookup table based at least in part upon the Beer-Lambert law.
13. The method of claim 1 , wherein the controller operates the one or more electromagnetic radiation emitters and one or more electromagnetic radiation detectors to function as a head-mounted pulse oximeter.
14. The method of claim 13 , wherein the controller is operatively coupled to an optical element coupled to the head-mounted member and viewable by the user, such that the output of the controller that is proportional to an oxygen saturation level in the blood vessel of the user may be viewed by the user through the optical element.
15. The method of claim 1 , wherein the one or more electromagnetic radiation detectors comprises a digital image sensor comprising a plurality of pixels, and wherein the controller is configured to automatically detect a subset of pixels which are receiving the light reflected after encountering at least one blood vessel of the eye of the user, and to use such subset of pixels to produce the output that is proportional to an oxygen saturation level in the blood vessel.
16. The method of claim 15 , wherein the controller is configured to detect the subset of pixels based at least in part upon reflected light luminance differences amongst signals associated with the pixels.
17. The method of claim 15 , wherein the controller automatically detects the subset of pixels based at least in part upon reflected light absorption differences amongst signals associated with the pixels.