Photoacoustic measurement of analyte concentration in the eye

• US 8,121,663 B2
• Filed: 10/11/2007
• Issued: 02/21/2012
• Est. Priority Date: 10/14/2005
• Status: Expired due to Fees

• Current Assignee: Gholam A. Peyman
• Original Assignee: Gholam A. Peyman
• Inventors: Peyman, Gholam A., Yoneya, Shin
• Primary Examiner(s): Winakur, Eric
• Assistant Examiner(s): Fardanesh, Marjan
• Application Number:
  US11/870,935
• Publication Number:
  US 20080033262A1
• Time in Patent Office: 1,594 Days
• Field of Search: 600309-360
• US Class Current: 600/319
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• 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

Abstract

In one aspect, the invention features a method and device for measuring blood concentration of a substance such as glucose in the aqueous humor by illuminating the aqueous humor with a light source at a frequency that is absorbed by the substance to the measured, and then sensing photoacoustically generated sound waves originated within the aqueous humor as a consequence of illumination by the light source. The blood concentration can be estimated from the amplitude of the sound waves received. The method may be combined with other optical techniques for glucose measurement and/or with optical or ultrasonic techniques for topographic mapping of eye structures.

Claims

1. A method of measuring the blood concentration of a substance in vivo, the method comprising

illuminating the aqueous or vitreous humor or retinal fluid with a light source at a frequency that is absorbed by the substance to be measured,

sensing only photoacoustically generated pulses or modulating acoustic signals originated within the aqueous or vitreous humor or retinal fluid as a consequence of illumination by the light source, without light being reflected or otherwise directed to a detector,

estimating blood concentration of the substance from an amplitude of received pulses or modulating acoustic signals, and

displaying the estimated blood concentration.

2. The method of claim 1 wherein the substance is blood glucose.

3. The method of claim 1 wherein the light source is a laser.

4. The method of claim 1 wherein the light source is a superluminescent diode.

6. The method of claim 1 wherein the illuminating with the light source comprises delivering pulsed light is delivered as pulses.

7. The method of claim 1 wherein the illuminating with the light source comprises delivering is delivered as modulated radiation.

8. The method of claim 1 wherein the received sensed acoustic signal is ultrasound.

5. An in vivo photoacoustic method of measuring the blood concentration of a substance, the method comprising

illuminating a retinal surface with a light source at a frequency that is absorbed by the substance to be measured,

sensing only photoacoustically generated pulses or modulating acoustic signals originated within the eye as a consequence of illumination by the light source, without light being reflected or otherwise directed to a detector,

estimating blood concentration of the substance from an amplitude of received pulses or modulating acoustic signals only, and

displaying the estimated blood concentration of the substance, the method photoacoustically measuring in vivo the blood concentration of the substance.

9. The method of claim 5 wherein the light source is a superluminescent diode.

10. The method of claim 5 wherein the substance is blood glucose.

11. The method of claim 5 wherein the light source is a laser.

12. The method of claim 5 wherein the illuminating with the light source comprises delivering pulsed light is delivered as pulses.

13. The method of claim 5 wherein the illuminating with the light source comprises delivering is delivered as modulated radiation.

14. The method of claim 5 wherein the sensed received acoustic signal is ultrasound.