Glucose concentration measuring method and apparatus
First Claim
1. A glucose concentration measuring method, comprising the steps of:
- i) irradiating a light beam from a predetermined light source to an eyeball of a subject that is located at a predetermined position;
ii) detecting intensities of first and second backward scattered lights of said light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said second backward scattered light is from an interface between said cornea and an anterior aqueous chamber of said eyeball;
iii) calculating a refractive index of an aqueous humor from said intensities of said first and second backward scattered lights; and
iv) calculating a concentration of glucose in said aqueous humor in accordance with a correlation between a predetermined refractive index of said aqueous humor and concentration of glucose in said aqueous humor, and in accordance with said calculated refractive index of said aqueous humor.
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Abstract
A light beam, which has been radiated out of a predetermined light source, is irradiated to the eyeball lying at a predetermined position. Each of intensity values of first and second backward scattered light beams of the light beam having been irradiated to the eyeball is detected. The first backward scattered light beam comes from an interface between the cornea of the eyeball and the ambient air, and the second backward scattered light beam comes from an interface between the cornea and the anterior aqueous chamber of the eyeball. A refractive index of the aqueous humor, which fills the anterior aqueous chamber, is calculated from the intensity values of the first and second backward scattered light beams. A concentration of glucose in the aqueous humor is calculated in accordance with correlation between the refractive index of the aqueous humor and the concentration of glucose in the aqueous humor, which correlation has been found previously, and in accordance with the calculated refractive index of the aqueous humor.
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Citations
48 Claims
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1. A glucose concentration measuring method, comprising the steps of:
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i) irradiating a light beam from a predetermined light source to an eyeball of a subject that is located at a predetermined position; ii) detecting intensities of first and second backward scattered lights of said light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said second backward scattered light is from an interface between said cornea and an anterior aqueous chamber of said eyeball; iii) calculating a refractive index of an aqueous humor from said intensities of said first and second backward scattered lights; and iv) calculating a concentration of glucose in said aqueous humor in accordance with a correlation between a predetermined refractive index of said aqueous humor and concentration of glucose in said aqueous humor, and in accordance with said calculated refractive index of said aqueous humor. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 24)
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2. A glucose concentration measuring method, comprising the steps of:
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i) splitting a low coherence light beam from a predetermined light source into a signal light beam and a reference light beam, each of which travels along or one of two different optical paths; ii) modulating at least one of said signal light beam and said reference light beam, wherein a slight difference in frequency occurs between them; iii) irradiating said signal light beam to an eyeball of a subject that is located at a predetermined position; iv) producing a first backward scattered light of said signal light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said reference light beam interferes with said first backward scattered light by adjusting an optical path length of said reference light beam to create a first interference light beam; v) measuring an intensity of said first interference light beam; vi) calculating an intensity of said first backward scattered light from said intensity of said first interference light beam; vii) producing a second backward scattered light of said signal light beam, said second backward scattered light is from an interface between an anterior aqueous chamber and said cornea of said eyeball, and said reference light beam interferes with said second backward scattered light by adjusting said optical path length of said reference light beam to create a second interference light beam; viii) measuring an intensity of said second interference light beam; ix) calculating an intensity of said second backward scattered light from said intensity of said second interference light beam; x) calculating a refractive index of an aqueous humor from said intensities of said first and second backward scattered lights; and xi) calculating a concentration of glucose in said aqueous humor in accordance with a correlation between a predetermined refractive index of said aqueous humor and concentration of glucose in said aqueous humor, and in accordance with said calculated refractive index of said aqueous humor.
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3. A glucose concentration measuring method, comprising the steps of:
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i) splitting a coherent light beam from a predetermined light source, the frequency of which is swept temporally in a sawtooth-like form, into a signal light beam and a reference light beam, each of which travels along one of two different optical paths; ii) irradiating said signal light beam to an eyeball of a subject that is located at a predetermined position; iii) producing a first backward scattered light of said signal light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said reference light beam interferes with said first backward scattered light and includes said coherent light beam, which has been radiated out of said light source with a difference in time in accordance with a difference between an optical path length of said signal light beam and said first backward scattered light and an optical path length of said reference light beam, and which has a difference in frequency with respect to said first backward scattered light, to create a first interference light beam; iv) measuring an intensity of said first interference light beam; v) calculating an intensity of said first backward scattered light from said intensity of said first interference light beam; vi) producing a second backward scattered light of said signal light, said second backward scattered light is from an interface between an anterior aqueous chamber and said cornea of said eyeball, and said reference light beam interferes with said first backward scattered light and includes said coherent light beam, which has been radiated out of said light ;
source with a difference in time in accordance with a difference between an optical path length of said signal light beam and said second backward scattered light and an optical path length of said reference light beam, and which has a difference in frequency with respect to said second backward scattered light, to create a second interference light beam;vii) measuring an intensity of said second interference light beam; viii) calculating an intensity of said second backward scattered light from said intensity of said second interference light beam; ix) calculating a refractive index of an aqueous humor from said intensities of said first and second backward scattered lights and x) calculating a concentration of glucose in said aqueous humor in accordance with a correlation between a predetermined refractive index of said aqueous humor and concentration of glucose in said aqueous humor, and in accordance with said calculated refractive index of said aqueous humor.
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4. A glucose concentration measuring method, comprising the steps of:
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i) irradiating an ultrashort pulsed light beam from a predetermined light source to an eyeball of a subject; ii) measuring intensities of first and second backward scattered lights of said ultrashort pulsed light beam by temporally separating said first and second backward scattered lights from each other, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said second backward scattered light is from an interface between an anterior aqueous chamber and said cornea of said eyeball; iii) calculating a refractive index of an aqueous humor from said intensities of said first and second backward scattered lights; and iv) calculating a concentration of glucose in said aqueous humor in accordance with a correlation between a predetermined refractive index of said aqueous humor and concentration of glucose in said aqueous humor, and in accordance with said calculated refractive index of said aqueous humor.
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5. A glucose concentration measuring method, comprising the steps of:
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i) irradiating a light beam from a predetermined light source to an eyeball of a subject that is located at a predetermined position; ii) detecting intensities of first and second backward scattered lights of said light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said second backward scattered light is from an interface between an anterior aqueous chamber and said cornea of said eyeball, said intensities are detected at a position that is conjugate with the corresponding interface by use of a confocal optical system, in which one of focusing points is set at each of said interfaces; iii) calculating a refractive index of an aqueous humor from said intensities of said first and second backward scattered lights and iv) calculating a concentration of glucose in said aqueous humor in accordance with a correlation between a predetermined refractive index of said aqueous humor and concentration of glucose in said aqueous humor, and in accordance with said calculated refractive index of said aqueous humor.
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22. A glucose concentration measuring method, comprising the steps of:
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i) irradiating a circularly polarized light beam from a predetermined light source to an eyeball of a subject that is located at a predetermined position, wherein said circularly polarized light beam impinges said eyeball at a predetermined angle of incidence; ii) detecting an elliptically polarized state of backward scattered light of said circularly polarized light beam, wherein said backward scattered light is from an interface between an anterior aqueous chamber and a cornea of said eyeball, the elliptically polarized state being detected at a position that is conjugate with said interface by use of a confocal optical system; iii) calculating a refractive index of an aqueous humor in accordance with said elliptically polarized state of said backward scattered light; and iv) calculating a concentration of glucose in said aqueous humor in accordance with a correlation between a predetermined refractive index of said aqueous humor and concentration of glucose in said aqueous humor, and in accordance with said calculated refractive index of said aqueous humor.
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25. A glucose concentration measuring apparatus, comprising:
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i) a light source for irradiating a light beam to an eyeball of a subject that is located at a predetermined position; ii) a photodetector for detecting intensities of first and second backward scattered lights of said light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said second backward scattered light is from an interface between said cornea and an anterior aqueous chamber of said eyeball; iii) a refractive index calculating means for calculating a refractive index of said aqueous humor from said intensities of said first and second backward scattered lights; iv) a storage section operable to store predetermined information representing a correspondence relationship between said refractive index of said aqueous humor and a concentration of glucose in said aqueous humor; and v) a glucose concentration calculating means for calculating a concentration of glucose in said aqueous humor in accordance with the stored correspondence relationship and the calculated refractive index of the aqueous humor. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 47, 48)
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26. A glucose concentration measuring apparatus, comprising:
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i) a light source device for radiating out a low coherence light beam to an eyeball of a subject; ii) an optical path splitting means for splitting said low coherence light beam into a signal light beam and a reference light beam, each of which travels along one of two different optical paths; iii) a modulation means, located in at least one of the two different optical paths, for modulating at least one of said signal light beam and said reference light beam, wherein a slight difference in frequency occurs between them; iv) an optical path length adjusting means for adjusting a length of said optical path which said reference light beam travels v) a wavefront matching means for; matching a wave front of a first backward scattered light of said signal light and a wave front of said reference light beam with each other, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air; and matching a wave front of a second backward scattered light of said signal light and a wave front of said reference light beam with each other, said second backward scattered light is from an interface between an anterior aqueous chamber and said cornea of said eyeball; vi) a photodetector for photoelectrically detecting an intensity of a first interference light beam, which is obtained from the matching of said wave front of said first backward scattered light and said wave front of said reference light beam with each other, and an intensity of a second interference light beam, which is obtained from the matching of wave front of said second backward scattered light and said wave front of said reference light beam with each other; vii) a heterodyne operation means for calculating intensities of said first and second backward scattered lights from said intensity of said first and second interference light beams, respectively; viii) a refractive index calculating means for calculating a refractive index of an aqueous humor from said intensities of said first and second backward scattered lights; ix) a storage section operable to store predetermined information representing a correspondence relationship between said refractive index of said aqueous humor and a concentration of glucose in said aqueous humor; and x) a glucose concentration calculating means for calculating a concentration of glucose in said aqueous humor in accordance with the stored correspondence relationship and the calculated refractive.
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27. A glucose concentration measuring apparatus, comprising:
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i) a light source device for radiating out a coherent light beam, the frequency of which is swept temporally in a sawtooth-like form; ii) an optical path splitting means for splitting said coherent light beam into a signal light beam irradiated to an eyeball of a subject and a reference light beam, each of which travels along one of two different optical paths; iii) a wavefront matching means for; matching a wave front of a first backward scattered light of said signal light beam and a wave front of said reference light beam with each other, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said reference light beam includes said coherent light beam, which has been radiated out of said light source device with a difference in time in accordance with a difference between an optical path length of said signal light beam and said first backward scattered light and an optical path length of said reference light beam, and which has a difference in frequency with respect to said first backward scattered light beam; and matching a wave front of a second backward scattered light of said signal light beam and a wave front of said reference light beam with each other, said second backward scattered light is from an interface between an anterior aqueous chamber and said cornea of said eyeball, and said reference light beam includes said coherent light beam, which has been radiated out of said light source device with a difference in time in accordance with a difference between said optical path length of said signal light beam and said second backward scattered light and said optical path length of said reference light beam, and which has a difference in frequency with respect to said second backward scattered light; iv) a photodetector for photoelectrically detecting an intensity of a first interference light beam, which is obtained from the matching of said wave front of said first backward scattered light and said wave front of said reference light beam, said reference light beam having a slight difference in frequency with respect to said first backward scattered light, and an intensity of a second interference light beam, which is obtained from the matching of said wave front of said second backward scattered light and said wave front of said reference light beam, said reference light beam having a slight difference in frequency with respect to said second backward scattered light; v) a heterodyne operation means for calculating an intensity of said first backward scattered light from said intensity of said first interference light beam, and calculating an intensity of said second backward scattered light from said intensity of said second interference light beam; vi) a refractive index calculating means for calculating a refractive index of said aqueous humor from said intensity of said first backward scattered light and said intensity of said second backward scattered light; vii) a storage section operable to store predetermined information representing a correspondence relationship between said refractive index of said aqueous humor and a concentration of glucose in said aqueous humor; and viii) a glucose concentration calculating means for calculating a concentration of glucose in said aqueous humor in accordance with the stored correspondence relationship and the calculated refractive index of the aqueous humor.
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28. A glucose concentration measuring apparatus, comprising:
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i) a light source device for radiating out an ultrashort pulsed light beam; ii) an optical time-domain backward scattering measurement means for irradiating said ultrashort pulsed light beam to an eyeball of a subject, and carrying out a time series measurement of intensities of first and second backward scattered lights of said ultrashort pulsed light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said second backward scattered light is from an interface between an anterior aquecus chamber and said cornea of said eyeball; iii) a refractive index calculating means for calculating a refractive index of an aqueous humor from said intensity of said first backward scattered light and said intensity of said second backward scattered light; iv) a storage section operable to store predetermined information representing a correspondence relationship between said refractive index of said aqueous humor and a concentration of glucose in said aqueous humor; and v) a glucose concentration calculating means for calculating a concentration of glucose in said aqueous humor in accordance with the stored correspondence relationship and the calculated refractive index of the aqueous humor.
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29. A glucose concentration measuring apparatus, comprising:
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i) a light source device for irradiating a light beam to an eyeball of a subject that is located at a predetermined position; ii) a confocal optical system for spatially separating first and second backward scattered lights of said light beam, wherein said first backward scattered light is from an interface between a cornea of said eyeball and ambient air, and said second backward scattered light is from an interface between an anterior aqueous chamber and said cornea of said eyeball; iii) a photodetector for detecting intensities of said first and second backward scattered lights that have been spatially separated from each other; iv) a refractive index calculating means for calculating a refractive index of said aqueous humor from said intensities of said first and second backward scattered lights; v) a storage section operable to store predetermined information representing a correspondence relationship between said refractive index of said aqueous humor and a concentration of glucose in said aqueous humor; and vi) a glucose concentration calculating means for calculating a concentration of glucose in said aqueous humor in accordance with the stored correspondence relationship and the calculated refractive index of the aqueous humor.
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46. A glucose concentration measuring apparatus, comprising:
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i) a light source device for irradiating a circularly polarized light beam to an eyeball of a subject that is located at a predetermined position, wherein said circularly polarized light beam impinges upon said eyeball at a predetermined angle of incidence; ii) a confocal optical system for extracting a backward scattered light of said circularly polarized light beam, wherein said backward scattered light is from an interface between an anterior aqueous chamber and a cornea of said eyeball; iii) an elliptically polarized state detecting means for detecting an elliptically polarized state of the extracted backward scattered light; iv) a refractive index calculating means for calculating a refractive index of an aqueous humor in accordance with said elliptically polarized state of said backward scattered light; v) a storage section operable to store predetermined information representing a correspondence relationship between said refractive index of said aqueous humor and a concentration of glucose in said aqueous humor; and vi) a glucose concentration calculating means for calculating a concentration of glucose in said aqueous humor in accordance with the stored correspondence relationship and the calculated refractive index of the aqueous humor.
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Specification