Fovioptics Inc.

Wilson Routt

Mark J Rice

James M Rioux

William T Williams

Robert H Sweat, Jr

Joe William Woods

Junli Ou

Blood glucose concentrations are measured by non-invasive methods and apparatus using visual pigment bleaching in conjunction with psychophysical methodologies. Bleaching light of selected wavelengths is projected through the pupil of the eye of an observer onto the fundus to bleach visual pigments in the eye. The observer's psychophysical response to a visual stimulus is then measured to obtain information regarding the rate of regeneration of the visual pigments. From the rate of pigment regeneration, blood glucose concentrations are measured accurately. The psychophysical methodologies that may be used with the invention include visual acuity tests and color-matching tests.

Non-invasive psychophysical measurement of glucose using photodynamics

The determination of blood glucose in an individual is carried out by projecting illuminating light into an eye of the individual to illuminate the retina with the light having wavelengths that are absorbed by rhodopsin and with the intensity of the light varying in a prescribed temporal manner. The light reflected from the retina is detected to provide a signal corresponding to the intensity of the detected light, and the detected light signal is analyzed to determine the changes in form from that of the illuminating light. For a biased sinusoidal illumination, these changes can be expressed in terms of harmonic content of the detected light. The changes in form of the detected light are related to the ability of rhodopsin to absorb light and regenerate, which in turn is related to the concentration of blood glucose, allowing a determination of the relative concentration of blood glucose. Other photoreactive analytes can similarly be determined by projecting time varying illuminating light into the eye, detecting the light reflected from the retina, and analyzing the detected light signal to determine changes in form of the signal due to changes in absorptivity of a photoreactive analyte.

Non-invasive measurement of blood analytes using photodynamics

Illuminating light of selected wavelengths in the visible or infrared range is projected through the pupil of the eye onto the fundus, and the light reflected back and out through the pupil is detected and analyzed, preferably using the area of the optic disk for analyzing the retinal vessels overlying the optic disk. Specific wavelengths of illuminating light may be chosen for each blood component to be analyzed depending on the spectral characteristics of the substance being analyzed. The reflected image from the retina may be used to measure non-photoreactive blood components such as hemoglobin, and photoreactive components such as bilirubin. For the measurement of photoreactive components, images may be taken before and after, or during, illumination of the eye with light at wavelengths which will affect the photoreactive analyte, enabling measurements of the concentration of the analyte.

Non-invasive measurement of blood components using retinal imaging

Non-invasive measurement of blood component using retinal imaging

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Lexington, KY, United States of America

Wilson Routt