A low coherence light beam is irradiated to the eyeball. A backward scattered light beam, which is reflected from each depth position in the eyeball, and a reference light beam, which is reflected from a mirror capable of moving, are caused to interfere with each other. A first backward scattered light beam, which comes from the interface between the cornea and the anterior aqueous chamber, and a second backward scattered light beam, which comes from the interface between the anterior aqueous chamber and the crystalline lens, are thus separated accurately from each other. An optical absorbance of the anterior aqueous chamber (the aqueous humor) is calculated from the intensities of the two backward scattered light beams. Each of a plurality of low coherence light beams having different wavelengths is irradiated to the eyeball, and the aforesaid operation is repeated. The concentration of glucose in the aqueous humor is measured by utilizing near-infrared spectroscopy. The measurement is thus achieved non-invasively and accurately.
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.
The present invention is related to optical non-invasive methods and instruments to detect the level of analyte concentrations in the tissue of a subject. The spectra of mid-infrared radiation emitted from a subject's body are altered corresponding to the concentration of various compounds within the radiating tissue. In one aspect of the invention, an instrument measures the level of mid-infrared radiation from the subject's body surface, such as the eye, and determines a specific analyte's concentration based on said analyte's distinctive mid-infrared radiation signature.
The present invention is related to non-invasive methods and instruments to detect the level of analyte concentrations in the tissue of a subject by measuring electromagnetic radiation signatures from the subject's conjunctiva. The spectra of mid-infrared radiation emitted from a subject's body are altered corresponding to the concentration of various compounds within the radiating tissue. In one aspect of the invention, an instrument floods the conjunctiva of the subject with electromagnetic radiation in the mid-infrared range and measures analyte concentrations based on mid-infrared radiation reflected back to the instrument.
The present invention is related to optical non-invasive methods and instruments to detect the level of analyte concentrations in the tissue of a subject. The spectra of mid-infrared radiation emitted from a subject's body are altered corresponding to the concentration of various compounds within the radiating tissue. In one aspect of the invention, an instrument floods a body surface of the subject, such as the subject's eye, with radiation in the mid-infrared range and measures analyte concentrations based on mid-infrared radiation reflected back to the instrument.
A method and apparatus for non-invasively measuring the concentration of an analyte, particularly blood analyte in blood. The method utilizes spectrographic techniques in conjunction with means for equilibrating the concentration of the analyte between the vascular system fluid compartment of the test area and the other tissue fluid compartment. An improved optical interface between a sensor probe and a skin surface or tissue surface of the body containing the blood to be analyzed. Multiple readings during the equilibration period are taken and utilized to show the direction and rate of charge of concentration of the analyte in the blood which is useful in optimizing therapeutic response to the collected data.
