Optical method and device for determining blood glucose levels

• US 5,713,353 A
• Filed: 04/19/1996
• Issued: 02/03/1998
• Est. Priority Date: 04/19/1996
• Status: Expired due to Fees

• Current Assignee: Jaime A. Castano
• Original Assignee: Jaime A. Castano
• Inventors: Castano, Jaime A.
• Primary Examiner(s): Lacyk, John P.
• Assistant Examiner(s): YARNELL, BRYAN KEITH
• Application Number:
  US08/634,849
• Time in Patent Office: 655 Days
• Field of Search: 128/630, 128/633, 128/645, 128/745, 128/897, 128/898, 351/206, 356/39
• US Class Current: 600/319
• 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: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/161 Flicker fusion testing eye testing A61B3/00

Abstract

Blood glucose levels of a person are determined by a device which provides a changing light pattern which changes in regard to one or several parameters defining its luminance, color, rate of flicker, spatial contrast, detail content, speed or otherwise provided that the change gradually stimulates one retinal system more than another retinal system. A person observes the changing light pattern until a subjective visual effect occurs, which is preferably an observer perceived dramatic change in the appearance of the light pattern, for example a change in the perceived direction of rotation. The subjective visual effect indicates a specific ratio of stimulation of the two retinal systems, for example the point of balanced stimulation of the two systems. Upon noting the subjective visual effect the patient actuates a mechanism which takes note of the current light pattern parameter values, allowing the device to relate such parameter values with a corresponding blood glucose level using predetermined calibration data. Thereby, the person'"'"'s glucose level is accurately determined in a completely non-invasive manner.

Claims

1. A method of determining a blood glucose level of a human subject, comprising:

providing a light pattern which provides a greater amount of stimulation to a first retinal system relative to a second retinal system, resulting in a first;

second stimulation ratio greater than one;

perceiving in the light pattern a characteristic that results from different sensitivities of the first retinal system and the second retinal system to the light pattern; and

determining a blood metabolite level of said subject from the perceived characteristic in the light pattern resulting from different properties of the first retinal system and the second retinal system.

2. The method of claim 1, wherein the first retinal system is an M-retinal system and the second retinal system is a P-retinal system.

3. A method of determining a blood glucose level of a person, comprising:

observing a light pattern having a parameter which changes gradually over time;

perceiving in the light pattern a subjective visual effect; and

indicating a blood glucose level of the person observing the light pattern from the light pattern parameter.

4. The method of claim 3, wherein at least a portion of the light pattern changes over time with respect to a parameter selected from the group consisting of color, luminance level, contrast, shape, size, detail content, texture, speed of movement, direction of movement and rate of flicker.

5. The method of claim 3, wherein the changing light pattern stimulates a first retinal system and a second retinal system.

6. The method of claim 5, wherein the changing light pattern stimulates two retinal systems which respond differently relative to each other with respect to changes in the light pattern and with respect to changes in blood glucose concentration.

7. The method of claim 6, wherein the changing light pattern stimulates the first retinal system and the second retinal system in a gradually changing ratio with respect to each other.

8. The method of claim 5, wherein the first retinal system is an M-system and the second retinal system is a P-system.

9. A method of determining a blood glucose level of a person having M-system and P-system retinal systems, comprising:

observing a light pattern which changes over time with respect to at least one parameter and which stimulates the M-retinal system and the P-retinal system in a changing ratio;

perceiving in the light pattern a subjective visual effect; and

relating a value of a changing parameter in the light pattern when the subjective visual effect is perceived to a blood glucose level of the person observing the light pattern.

10. The method of claim 9, wherein the subjective visual effect represents a predetermined measured degree of relative stimulation of the M-retinal system and the P-retinal system.

11. The method of claim 9, wherein the subjective visual effect occurs at M-P crossover point.

12. The method of claim 9, wherein the light pattern changes over time with respect to a characteristic selected from the group consisting of color, luminance level, contrast, shape, size, detail content, texture, speed of movement, direction of movement and rate of flicker.

13. The method of claim 12, wherein the light pattern consists of a flickering light, and the subjective visual effect is a visual effect selected from the group consisting of appearance of colors, appearance of a regular geometric pattern and cessation of radial movement.

14. The method of claim 9, wherein the light pattern is selected from the group consisting of a series of windmills and wheel images, and the subjective visual effect is a reversal in the direction of rotation of the light pattern.

15. A device for measuring the glucose level of a person, comprising:

a body member; and

a means for generating a light pattern connected to the body member, wherein the light pattern stimulates a first retinal system and a second retinal system in a manner such that an observer will note a subjective visual characteristic in the light pattern which indicates a known blood glucose level of the person.

16. The device of claim 15, wherein the first retinal system is an M-retinal system and the second retinal system is a P-retinal system.

17. The device of claim 16, wherein the subjective visual characteristic is direction of apparent rotation.

18. A device for determining the blood glucose level of a person, comprising:

a body member;

a means for generating a changing light pattern that changes over time with respect to at least one parameter, wherein the light pattern changes in a controlled manner and stimulates two complementary retinal systems in a continuously changing ratio of stimulation;

an actuation means which is actuated to indicate the presence of a subjective visual effect, and which initiates measurement of the parameter as the light pattern when actuated;

a microprocessor comprising a memory and software programming, which relates measured parameter values to a predetermined blood glucose level; and

a means for displaying information about blood glucose levels.

19. The device of claim 18, wherein the light pattern changes over time with respect to one or several parameters selected from the group consisting of color, luminance level, contrast, shape, size, detail content, texture, speed of movement, direction of movement and rate of flicker.

20. The device of claim 19, wherein the light pattern comprises a flickered light of variable flicker rate.

21. The device of claim 19, wherein the light pattern comprises a series of images which create a windmill or wheel pattern that appears to rotate.

22. The device of claim 18, wherein the two complementary retinal systems comprise an M-retinal system and a P-retinal system, and said changing ratio of stimulation passes through a point where the M-retinal system and the P-retinal systems are stimulated equally.

23. The device of claim 18, wherein the microprocessor includes information on a range of parameter values associated with the presence of a subjective visual effect, along with corresponding blood glucose levels.

24. The device of claim 18, wherein the microprocessor is programmed to avoid erroneous measurements by making redundant measurements, checking the consistency of the user'"'"'s responses and canceling any effect created by user'"'"'s reaction time.

25. The device of claim 18, wherein the microprocessor is programmed to avoid erroneous measurements by continuously diagnosing and testing components of the device and aborting measurement to avoid anomalous results.