Non-invasive glucose meter
First Claim
1. A method of determining the concentration of a substance in an eye, the method comprising:
- providing a nearly parallel measurement light beam having a first wavelength at which the substance has a non-zero first absorption coefficient;
providing a nearly parallel reference light beam having a second wavelength at which the substance has a second absorption coefficient which is substantially equal to zero;
irradiating the retina of the eye with the measurement light beam;
irradiating the retina of the eye with the reference light beam;
reflecting at least a portion of the measurement light beam from the retina, thereby producing a retro-reflected measurement light beam having the first wavelength;
reflecting at least a portion of the reference light beam from the retina, thereby producing a retro-reflected reference light beam having the second wavelength;
generating a measurement signal in response to the retro-reflected measurement light beam;
generating a reference signal in response to the retro-reflected reference light beam; and
determining the concentration of the substance in the eye in response to the measurement signal and the reference signal.
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Accused Products
Abstract
An apparatus and method for measuring a concentration of a substance in an eye using a retro-reflected measurement light beam having a first wavelength at which the substance has a non-zero first absorption coefficient and a retro-reflected reference light beam having a second wavelength at which the substance has a second absorption coefficient which is substantially equal to zero. The apparatus further includes a detector positionable to receive the retro-reflected measurement light beam and the retro-reflected reference light beam. The detector is responsive to light having the first wavelength by generating a measurement signal and responsive to light having the second wavelength by generating a reference signal. The apparatus further includes an electrical circuit coupled to the detector. The electrical circuit is responsive to the measurement signal and the reference signal to measure the concentration of the substance in the eye.
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Citations
18 Claims
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1. A method of determining the concentration of a substance in an eye, the method comprising:
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providing a nearly parallel measurement light beam having a first wavelength at which the substance has a non-zero first absorption coefficient; providing a nearly parallel reference light beam having a second wavelength at which the substance has a second absorption coefficient which is substantially equal to zero; irradiating the retina of the eye with the measurement light beam; irradiating the retina of the eye with the reference light beam; reflecting at least a portion of the measurement light beam from the retina, thereby producing a retro-reflected measurement light beam having the first wavelength; reflecting at least a portion of the reference light beam from the retina, thereby producing a retro-reflected reference light beam having the second wavelength; generating a measurement signal in response to the retro-reflected measurement light beam; generating a reference signal in response to the retro-reflected reference light beam; and determining the concentration of the substance in the eye in response to the measurement signal and the reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for measuring a concentration of a substance in an eye having a retina, the apparatus comprising:
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a measurement light source producing a nearly parallel measurement light beam having a first wavelength, the substance having a non-zero first absorption coefficient for light at the first wavelength, wherein the measurement light source is positionable such that at least a portion of the measurement light beam retro-reflects from the retina; a reference light source producing a nearly parallel reference light beam having a second wavelength, the substance having a second absorption coefficient which is substantially equal to zero for light at the second wavelength wherein the reference light source is positionable such that at least a portion of the reference light beam retro-reflects from the retina; a detector responsive to light having the first wavelength by generating a measurement signal and responsive to light having the second wavelength by generating a reference signal; and an electrical circuit operatively coupled to the detector, the electrical circuit responsive to the measurement signal and the reference signal to measure the concentration of the substance in the eye. - View Dependent Claims (10, 11, 12, 13)
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14. A substance-measuring meter comprising:
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an optical system adapted to irradiate the retina of an eye with a nearly parallel measurement light beam having a first wavelength at which a substance has a non-zero first absorption coefficient and adapted to irradiate the retina of the eye with a nearly parallel reference light beam having a second wavelength at which the substance has a second absorption coefficient which is substantially equal to zero, such that at least a portion of the measurement light beam and at least a portion of the reference light beam are retro-reflected from the retina, thereby producing a retro-reflected measurement light beam having the first wavelength and a retro-reflected reference light beam having the second wavelength; a detection system adapted to generate a measurement signal in response to the retro-reflected measurement light beam and to generate a reference signal in response to the retro-reflected reference light beam; and an electronic circuit responsive to at least the measurement signal and the reference signal by determining the concentration of the substance in the eye. - View Dependent Claims (15, 16)
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17. A method of using a meter adapted to measure a concentration of a substance in an eye, the method comprising:
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irradiating the retina of the eye with a nearly parallel first light beam having a first wavelength; irradiating the retina of the eye with a nearly parallel second light beam having a second wavelength; receiving at least a portion of the first light beam retro-reflected from the retina; receiving at least a portion of the second light beam retro-reflected from the retina; generating a first signal in response to the received portion of the retro-reflected first light beam; generating a second signal in response to the received portion of the retro-reflected second light beam; and determining the concentration of the substance in the eye in response to at least the first signal and the second signal. - View Dependent Claims (18)
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Specification