Method and apparatus for monitoring blood-glucose concentration by measuring focal properties of the eye
First Claim
1. A method of obtaining information related to blood-glucose concentration in a living subject, comprising the steps of:
- obtaining a test measure of the optical power of at least one eye of such subject; and
then comparing the test measure with a calibration measure of optical power that corresponds to a reference blood-glucose level in such subject, to obtain such glucose-related information.
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Abstract
Optical power of a living subject'"'"'s eye is measured and compared with a calibration value that corresponds to a reference blood-glucose level. The reference level is determined conventionally, as by blood analysis. Optical power of the eye increases with blood-glucose level. The comparison can include interpolation or extrapolation from two or more calibration points. Optical power is measured by projecting an image through an external optical system and through the cornea and lens of the subject'"'"'s eye onto the subject'"'"'s retina--while monitoring sharpness of focus at the retina, and systematically modifying the conditions of projection of the image. The relation between sharpness and projection conditions provides the measure of glucose concentration. For example, for presbyopic subjects, (1) the optical power of the external system may be varied, and the value of power that produces sharpest retinal focus may be used as the measure, or (2) the power may be held constant while the object distance is varied, and the distance that yields sharpest focus may be the measure. As another example, in nonpresbyopes the shortest or longest distance at which a subject can sharply focus may serve as the measure; this may be found by fixing the optical power of the external system and varying the object distance.
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Citations
33 Claims
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1. A method of obtaining information related to blood-glucose concentration in a living subject, comprising the steps of:
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obtaining a test measure of the optical power of at least one eye of such subject; and then comparing the test measure with a calibration measure of optical power that corresponds to a reference blood-glucose level in such subject, to obtain such glucose-related information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. Apparatus for obtaining information related to blood-glucose concentration in a living subject who has at least one eye that includes a lens and a retina;
- said apparatus comprising;
means for projecting, under adjustable projection conditions, an image of an object through an external optical system and through such eye lens onto such retina; means for adjusting the projection conditions of the external optical system in response to the optical power of said eye; and an indicator, responsive to the adjusting means and graduated in units of blood-glucose concentration, for indicating the approximate blood-glucose concentration in such subject that corresponds to the projecton conditions of the external optical system. - View Dependent Claims (29, 30)
- said apparatus comprising;
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22. Apparatus for obtaining information related to blood-glucose concentration in a living subject who has at least one eye that includes a lens and a retina;
- said apparatus comprising;
means for projecting, under adjustable projection conditions, an image of an object through an external optical system and through such eye lens onto such retina; means for adjusting the projection conditions of the external optical system; and an indicator, responsive to the adjusting means and graduated in units of blood-glucose concentration, for indicating the approximate blood-glucose concentration in such subject that corresponds to the projection conditions of the external optical system wherein the adjustable projection conditions comprise the optical power of the external optical system.
- said apparatus comprising;
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23. Apparatus for obtaining information related to blood-glucose concentration in a living subject who has at least one eye that includes a lens and a retina;
- said apparatus comprising;
means for projecting, under adjustable projection conditions, an image of an object through an external optical system and through such eye lens onto such retina; means for adjusting the projection conditions of the external optical system; and an indicator, responsive to the adjusting means and graduated in units of blood-glucose concentration, for indicating the approximate blood-glucose concentration in such subject that corresponds to the projection conditions of the external optical system wherein the adjustable projection conditions comprise the effective distance of the object from such eye lens. - View Dependent Claims (26, 27, 28)
- said apparatus comprising;
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24. Apparatus for obtaining information related to a blood-glucose concentration in a living subject who has at least one eye that includes a lens and a retina;
- said apparatus being paritcularly adapted for such subjects that are presbyopic, said apparatus comprising;
means for projecting, under adjustable projection conditions, an image of an object through an external optical system and through such eye lens onto such retina; means for adjusting the projection conditions of the external optical system; an indicator, responsive to the adjusting means and graduated in units of blood-glucose concentration, for indicating the approximate blood-glucose concentation in such subject that corresponds to the projection conditions of the external optical system; automatic means for sensing sharpness of focus of the image on such retina; means responsive to the automatic sensng means, for controlling the adjusting means to maximize the sharpness; and whereby the apparatus automatically focuses the image on such retina to maximum sharpness and indicates the blood-glucose concentration level in such subject that corresponds to the power of the external optical system.
- said apparatus being paritcularly adapted for such subjects that are presbyopic, said apparatus comprising;
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25. Apparatus for obtaining information related to blood-glucose concentration in a living subject who has at least one eye that includes a lens and a retina;
- said apparatus being particularly adapted fro such subjects that are presbyopic, said apparatus comprising;
means for projecting, under adjustable projection conditions, an image of an object through an external optical system and through such eye lens onto such retina; means for adjusting the projection conditions of the external optical system; and an indicator responsive to the adjusting means and graduated in units of blood-glucose concentration, for indicating the approximate blood-glucose concentration in such subject that corresponds to the projection conditions of the external optical system and wherein; the adjusting means are manually adjustable by such living subject; and the sharpness of focus of the image on such retina is perceptible by such subject'"'"'s own visual sensation of the image on such retina; whereby such subject can focus the image on such retina to maximum sharpness and can read from the indicator such subject'"'"'s own blood-glucose concentration level that corresponds to the power of the external optical system.
- said apparatus being particularly adapted fro such subjects that are presbyopic, said apparatus comprising;
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31. Apparatus for obtaining information related to blood-glucose concentration in a living subject who has at least one eye that includes a lens and a retina;
- said apparatus being particularly for use if such subject'"'"'s eye has glycemia-induced astigmatism and such astigmatism is characterized by an axis meridian, and comprising;
means for projecting, under adjustable projection conditions, an image of an object through an external optical system and through such eye lens onto such retina; the image of said object on such retina including a plurality of parallel lines that are aligned substantially perpendicular to the axis meridian of glycemia-induced astigmatism in such subject'"'"'s astigmatic eye; means for adjusting the projection conditions of the external optical system in response to the optical power of said eye; and an indicator, responsive to the adjusting means, for providing as indication related to the projection conditions of the external optical system; whereby the indicator provides an indication related to the approximate blood-glucose concentration in such subject that corresponds to the projection conditions; and whereby sharpness of focus of the image onto such retina is substantially independent of glycermia-induced astigmatism exceeding that which corresponds to said predetermined blood-glucose reference level.
- said apparatus being particularly for use if such subject'"'"'s eye has glycemia-induced astigmatism and such astigmatism is characterized by an axis meridian, and comprising;
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32. Apparatus for obtaining information related to blood-glucose concentration in a living subject whose has at least one eye that includes a lens and a retina;
- said apparatus being particularly for use with such subjects whose eye-pupil dilation capability is substantially normal to at least well beyond five-millimeter pupil diameter, and comprising;
means for projecting, under adjustable projection conditions, an image of an object through an external optical system and through such eye lens onto such retina, said image appearing on a field, and said image and field being characterized by brightness; means for adjusting the brightness of the image to a level that causes the pupil diameter of such subject'"'"'s eye to be approximately five millimeters; means for adjusting the projection conditions of the external optical system in response to the optical power of said eye; and an indicator, responsive to the adjusting means, for providing an indication related to the projection conditions of the external optical system; whereby the indicator provides an indication related to the approximate blood-glucose concentration in such subject that corresponds to the projection conditions; and whereby the relationship between said indication and such glucose concentration has a sensitivity that is substantially optimized for depth of field and aberrations. - View Dependent Claims (33)
- said apparatus being particularly for use with such subjects whose eye-pupil dilation capability is substantially normal to at least well beyond five-millimeter pupil diameter, and comprising;
Specification