Measuring Blood Glucose Concentration

• US 20080033261A1
• Filed: 05/28/2004
• Published: 02/07/2008
• Est. Priority Date: 05/28/2003
• Status: Abandoned Application

• Current Assignee: Nicm AG
• Original Assignee: Nicm AG
• Inventors: Zeller, Philipp N.
• Application Number:
  US10/558,568
• Publication Number:
  US 20080033261A1
• Time in Patent Office: Days
• US Class Current: 600/319
• CPC Class Codes: A61B 3/1225 using coherent radiation
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G01N 21/49 within a body or fluid
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

Apparatus for measuring blood glucose concentration comprises a laser source (14) capable of producing a radiation beam from a tunable laser, a collimator (12, 13) for collimating the radiation beam (21) to a small diameter, an optical arrangement (12, 13) for directing the collimated beam (21) through the anterior chamber (23) of an eye (22) in a direction such that it forms a angle of between 75° and 105° to the line of sight (24) of the eye so that the beam does not directly strike the retina (26) and in particular the macular (27). A spectrometer (1-6) is provided to measure the intensity of Raman scattered radiation at different wavelengths. Signal processing means (15) derives the blood glucose concentration from the measured intensities. In one embodiment the laser is tunable between 500 nm. and 700 nm. and the laser beam is collimated to a diameter of between 1 μm and 200 μm.

Claims

1. A method of measuring blood glucose concentration comprising the steps of;

a) producing a laser beam from a narrow bandwidth laser source, or a tunable laser source, or from a plurality of narrow bandwidth laser sources,

b) collimating the laser beam to a small diameter and passing it through the anterior chamber of an eye in a direction such that the beam does not directly strike the retina nor directly enter the posterior chamber of the eye (vitreal body),

c) observing Raman scattered light in a direction transverse to the incident laser beam,

d) measuring the intensity of the scattered radiation at different wavelengths, and

e) deriving the blood glucose concentration from the measured intensities.

2. A method as claimed in claim 1 wherein in step a) a tunable continuous wave laser is used that is tunable in a wavelength range between 500 nm and 700 nm.

3. A method as claimed in claim 1 wherein in step b) the laser beam is collimated to a diameter of between 1 μ

m and 200 μ

m.

4. A method as claimed in claim 1 in which in step b) the incident angle of the laser beam is 90°

±

15°

to the line of sight of the eye.

5. A method as claimed in claim 1 including the step of absorbing refracted light issuing from the other side of the eye.

6. A method as claimed in claim 1 in which in step c) the Raman scattered light is observed at an angle of between 50°

and 130°

to the incident beam.

7. A method as claimed in claim 1 comprising the further step of subtracting fluorescence spectra from the total detected spectra to obtain the Raman spectra.

8. Apparatus for measuring blood glucose concentration comprising a laser source capable of producing a radiation beam from a tunable laser, a collimator for collimating the radiation beam to a small diameter, an optical arrangement for directing the collimated beam through the anterior chamber of an eye in a direction such that it forms an angle of between 75°

and 105°

to the line of sight of the eye so that the beam does not strike the retina, a spectrometer for measuring the intensity of Raman scattered radiation at different wavelengths, and signal processing means for deriving the blood glucose concentration from the measured intensities.

9. Apparatus as claimed in claim 8 in which the laser is tunable between 500 nm and 700 nm.

10. Apparatus as claimed in claim 8 in which the laser beam is collimated to a diameter of between 1 μ

m and 200 μ

m.

11. Apparatus as claimed in claim 8 comprising means for absorbing refracted light issuing from the other side of the eye.

12. Apparatus as claimed in claim 8 in which the spectrometer receives Raman scattered light at an angle of between 50°

and 130°

to the incident beam.

13. Apparatus as claimed in claim 8 in which the scattered intensity is measured at two or more different wavelengths.