Device and method for determining glucose concentration

Abstract

The invention relates to a device (10) for determining a glucose concentration in an anterior chamber (12) of a user's eye (14), comprising: a VCSEL (11) emitting a laser light (16); the VCSEL (11) and the optical element (241, 242, 243, 244) are designed such that the laser light (16) enters the anterior chamber (12) of the eye, the emergent light (20) from the anterior chamber (12) penetrates into the VCSEL (11), and the glucose concentration can be determined by means of an analysis unit (13) which analyzes the self-mixing interference generated in the VCSEL (11). A method for determining a glucose concentration using the device and a glasses unit having the device (10) are also disclosed.

Description

Technical Field

[0001] The invention relates to a device and a method for determining the glucose concentration according to the main claims. Background Art

[0002] Glucose measurement as a therapeutic support measure already had a major impact on the treatment of diabetes more than 30 years ago. The decisive breakthrough was the availability of small, portable blood glucose meters, which require only a small amount of blood as sample material and display the measurement result after a short time. One result of this development is the widespread use of intensive insulin therapy (ICT), which enables insulin to be adjusted depending on the amount of food consumed or in the event of elevated glucose levels.

[0003] However, the biochemical reactions associated with the use of enzymatic glucose conversion are associated with the collection of blood samples (SMBG - self-monitoring of blood glucose). Although modern devices require only a few drops of blood with a volume of less than 1 μl and blood collection devices and blood collection needles enable blood collection with very little or no pain, the self-injury necessary in each case cannot be avoided.

[0004] Even with the availability of continuous glucose monitoring (CGM) systems, this has changed only to a limited extent. These systems enable people with diabetes to obtain a complete glucose history over a period of up to 14 days. But also in this case, at least one self-injury is required when inserting the glucose sensor into the subcutaneous fat tissue. In addition, even with factory-calibrated systems that do not require invasive SMBG for calibration, such calibration is necessary to check the measurements of the CGM system or in the event that the glucose values ​​are not reliable.

[0005] In general, invasive glucose measurements are painful for the person, take time, and result in high consumable costs. Summary of the invention

[0006] An object achieved by the present invention is to provide non-invasive glucose measurement.

[0007] For this purpose, it is proposed to provide a device for determining the glucose concentration in the anterior chamber of the eye of a user, the device having: a VCSEL, which emits laser light; and an optical element for influencing the laser light, wherein the VCSEL (Vertical Cavity Surface Emitting Laser) and the optical element are designed so that the laser light enters the anterior chamber of the eye, wherein the exiting light from the anterior chamber of the eye penetrates into the VCSEL, and by means of an analysis unit that analyzes the self-mixing interference generated in the VCSEL, the glucose concentration can be determined. Preferably, the VCSEL has a polarization grating.

[0008] Non-invasive glucose measurement is performed by measuring the user's eye with a laser. The fluid of the anterior chamber, which consists of 98% water, contains three optically active elements (glucose, albumin, ascorbic acid). The laser beam should be coupled into the anterior chamber and interact with the fluid. A lower limit wavelength of >800nm ​​is selected to prevent strong absorption and uncomfortable heating of the eye. The upper limit wavelength is <1500nm.

[0009] Non-invasive glucose measurement makes use of the fact that glucose is an enantiomer and chiral in the anterior chamber. Laser light propagating through a liquid containing glucose experiences birefringence. If linearly polarized light is now emitted, the field vector oriented according to the polarization is rotated by the chiral glucose by an angular amount that is proportional to the glucose concentration in the liquid in the anterior chamber. By determining the angular amount of rotation, the glucose concentration in the anterior chamber and therefore the blood sugar level can be inferred.

[0010] Laser light is coupled into the eye chamber and interacts with the chiral liquid. The exiting light from the eye chamber is then analyzed in terms of the angular amount of rotation of the polarization.

[0011] Due to the small size of the anterior eye chamber, the interaction distance is very short and a highly sensitive measurement system is therefore required. Therefore, a further improvement of the VCSEL could be equipped with a photodiode.

[0012] The outgoing light fed back into the VCSEL, whose polarization vector is rotated by a certain angular amount, is partially coupled back into the resonator and detected by a photodiode at the resonator. The detected signal is generated by the coherent interference of the laser resonator field representing a standing wave and the feedback component of the outgoing light. The resulting self-mixing interference exhibits a good signal-to-noise ratio, which can be analyzed to a large extent. This means that a glucose concentration reading can be obtained with only a small error. The self-mixing interference and the photodiode are analyzed by a connected analysis unit.

[0013] Preferably, a polarization grating can be attached to the outcoupling facet of the VCSEL. The polarization grating polarizes the light emitted from the outcoupling facet and filters the outgoing light entering the VCSEL. In this regard, the power component of the outgoing light in the resonator coupled to the VCSEL depends on the glucose content or the angular amount of rotation in the intraocular fluid, because only a portion of the outgoing light directed to the polarization grating can return to the VCSEL or the photodiode. The rest is filtered out by the polarization grating.

[0014] Furthermore, using self-mixing interference, light with the same polarization as the light inside the cavity can be detected, since light with different polarizations does not cause interference.

[0015] Furthermore, VCSELs with integrated photodiodes are particularly space-saving and weight-saving and, compared to edge emitters, have approximately five times the temperature stability with regard to the temperature dependence of the emission wavelength.

[0016] Non-invasive glucose measurement eliminates the need for needles, making it possible to determine blood sugar levels without damaging a person's skin. Thus, the risk of infection due to contaminated needles or pain caused by needles is avoided.

[0017] Compared to invasive glucose measurement, since no needle is used for non-invasive glucose measurement, no consumables are required for non-invasive glucose measurement. Therefore, non-invasive glucose measurement provides a method that generally provides increased ecological and economic efficiency.

[0018] The VCSEL has an emission region on its surface from which laser light is emitted from the VCSEL.

[0019] The present invention can also be implemented using a VCSEL array comprising a plurality of VCSELs.

[0020] Further developments and exemplary embodiments of the invention are provided in the dependent claims.

[0021] Advantageously, it can be provided that the first optical element has a mirror surface, wherein the mirror surface is arranged in the beam path of the outgoing light so that the outgoing light is reflected on the mirror surface. The laser light and the outgoing light propagate along the beam path. The beam path determines the direction of the laser light or the outgoing light. By means of the first optical element, the outgoing light can be reflected back into the anterior chamber, where it strikes the chiral liquid again, or at least partially through the anterior chamber along the beam path defined by the mirror surface. The optical element enables different beam paths to be realized.

[0022] Preferably, the anterior chamber is positioned between the VCSEL and the first optical element. In this regard, the laser light of the VCSEL enters the anterior chamber and after leaving the chamber, the laser light, now the exit light from the chamber, strikes the mirror surface of the optical element. For example, the anterior chamber is positioned between the VCSEL and the first optical element by positioning the device in the area of ​​the user's face.

[0023] In a specific further development, the laser light from the VCSEL preferably directly enters the anterior eye chamber and the exiting light is directly emitted onto the mirror surface. In this respect, the laser light from the VCSEL can be emitted into the anterior eye chamber without being affected by optical elements.

[0024] Alternatively or in addition, the light emitted from the VCSEL can be focused into the anterior chamber. For this purpose, an optical element in the form of a refractive lens and / or a diffractive lens and / or a lens made of a photonic metamaterial can be used, which is arranged between the VCSEL and the chamber. Such an optical element can be attached directly to the emission area, thereby providing a single-piece VCSEL with the optical element. This results in a high intensity in the anterior chamber and a correspondingly strong interaction of the light with the chiral liquid.

[0025] This optical element designed as a lens can be combined with all exemplary embodiments. Here, the lens can be arranged in both the beam path of the laser and the beam path of the exit light, and can be combined with other optical elements in a way that efficiently utilizes the light from the VCSEL. In particular, the beam can be focused and / or collimated by the lens. In this regard, the beam can be focused into the anterior eye chamber and / or onto the emission area.

[0026] Particularly preferably, the anterior chamber is arranged between the first optical element and the VCSEL, and the mirror surface is preferably oriented perpendicular to the beam path of the exiting light so that the exiting light is reflected back into the anterior chamber. The exiting light reflected at the first optical element, preferably directly re-entering the anterior chamber, leaves the anterior chamber again after re-entry to be coupled into the VCSEL. This may cause the re-entering exiting light to be further rotated by a certain angular amount, so that the light exiting for the second time has an additionally rotated polarization direction.

[0027] It can be provided that the anterior chamber is positioned between the first optical element and the second optical element so that the beam path of the laser passes through the anterior chamber. If the device is positioned in the area of ​​the user's face, the chamber is arranged between the first optical element and the second optical element in the following manner: the laser light from the VCSEL is first reflected at the second optical element in the direction of the anterior chamber and then penetrates into the anterior chamber. Then, the exit light from the chamber is projected onto the first optical element. The exit light reflected at the first optical element does not reenter the anterior chamber. Since the first optical element is not oriented perpendicularly to the beam path of the exit light, the exit light is guided through the anterior chamber. The first optical element forms an angle different from 90° with the beam path of the exit light from the chamber and is sufficient to guide the reflected light through the chamber. Preferably, the exit light that has passed is at least indirectly coupled into the VCSEL after further reflection at the second optical element. Preferably, a lens is arranged in the emission region where the return light is recoupled into the VCSEL, which enables the light to be coupled more easily and ensures that it meets the resonance conditions required for intracavity interference of the VCSEL. For example, refractive lenses, diffractive lenses, and / or lenses made of metamaterials may be used.

[0028] In particular, the beam path of the laser light from the VCSEL may extend directly to the second mirror.The laser light is emitted from the VCSEL directly onto the second optical element where it is preferably reflected such that the beam path preferably extends directly into the anterior eye chamber.

[0029] In a preferred further development, the beam paths of the laser light cross at least once. For example, the beam path of the laser light from the VCSEL can cross the beam path of the exit light. Since the beam path of the exit light and the beam path of the laser light are located in the same spatial volume portion, this enables a particularly compact design of the device.

[0030] In addition, the beam path of the reflected exit light extends from the first optical element to the second optical element. Therefore, the exit light is reflected at the first optical element and propagates in the direction of the second optical element, where the exit light is reflected again. Preferably, the exit light is then coupled into the VCSEL to achieve self-mixing interference.

[0031] A filter for the exit light can be provided by a third optical element, which produces a phase delay of a quarter wavelength when the laser passes through the third optical element. In order to ensure a particularly efficient filtering effect, the third optical element is positioned between the anterior chamber and the VCSEL in the beam path of the laser and the exit light from the VCSEL. The linearly polarized exit light rotated by a certain angular amount relative to the laser from the VCSEL by the chiral liquid in the anterior chamber is circularly polarized by a so-called quarter wave plate, which can constitute the third optical element. This makes it possible to distinguish the exit light from the scattered light based on polarization. If the laser from the VCSEL also passes through the quarter wave plate and the linear polarization of the laser is oriented in the direction of the optical axis of the quarter wave plate, the laser remains linearly polarized. This means that the laser from the VCSEL and the exit light from the anterior chamber have different polarizations and can be distinguished from each other.

[0032] Preferably, a fourth optical element may be provided, which replaces the third optical element or is added to the third optical element. The fourth optical element may be a liquid crystal module, which polarizes the laser light before it enters the anterior eye chamber. Preferably, the polarization is rotated by a certain angle by the liquid crystal.

[0033] The liquid crystal module is controlled by a driver device so that the liquid crystal module modulates the laser light, for example, periodically, into at least two different polarization modes. For example, in one modulation state, the laser light may have a polarization that coincides with the optical axis of the third optical element; and in another modulation state, the polarization direction of the laser light may be tilted by a certain angle relative to the optical axis of the third optical element, wherein the third optical element is a quarter wave plate. In particular, the frequency of setting the different polarization modes is higher than the frequency of average eye movement, so that the polarization mode changes at least once when the eye is stationary. In crystal optics, the optical axis refers to the direction along which each polarization component of the beam has the same refractive index in an optically anisotropic (birefringent) crystal. It should not be confused with the optical axis of the optical system.

[0034] In a further development of the invention, the reference VCSEL may emit a reference laser whose polarization is selected such that it reacts to a lesser extent with the chiral liquid in the eye chamber than the laser of the above-mentioned VCSEL of the device. Preferably, this reference laser is fully circularly polarized when coupled into the anterior eye chamber, since circularly polarized light does not interact with the chiral liquid in the same way as linearly polarized light.

[0035] The reference laser light of the reference VCSEL may be co-linear with the laser light of the VCSEL, wherein, in particular, an optical system comprising optical fibers guides the reference laser light of the reference VCSEL and the laser light of the VCSEL along a common beam path.

[0036] The device including the VCSEL and at least one optical element can be incorporated into an eyeglass unit that is arranged to be worn by a user and has the device, so that the user of the eyeglass unit can determine his or her own blood glucose level. For example, the eyeglass unit can be data glasses, virtual reality glasses, augmented reality glasses, or conventional vision-aiding glasses. The device can be integrated into an eyeglass frame. In addition, a battery can be attached to the eyeglass unit to power the device.

[0037] According to the method, in order to determine the glucose concentration in the anterior chamber of the user's eye using the device, laser light is emitted from the VCSEL, wherein the laser light enters the anterior chamber and then exits from the anterior chamber, and the exit light is then received by the VCSEL. Within the VCSEL, the light coupled into the cavity of the VCSEL generates self-mixing interference. An analysis unit connected to the VCSEL, preferably having a microcontroller, analyzes the self-mixing interference with respect to the glucose concentration in the anterior chamber, thereby determining the glucose concentration.

[0038] A simple and advantageous method can be used to determine the glucose concentration regularly at specific time intervals. The glucose measurement can start after a period in which no measurement is performed. The time intervals can have the same length or be individually programmed. For example, the time intervals can be selected so that the glucose measurement is performed at mealtimes, because there is a high probability that the blood glucose level will rise due to technical reasons as a result of food intake. Another alternative is to measure the blood glucose level continuously as long as the device is placed on the eyes, for example with the aid of a pair of glasses. With each method, the time resolution of the measurement is different, and the measurement results obtained are created and stored in the memory of the device according to a chronological record (Protokoll) of the glucose concentration at different time points. For example, the record is available in digital form and can be read from the device via radio or a physical interface such as USB.

[0039] For example, the record may be transmitted from the device to a computing device such as a smartphone or to the cloud where it is further processed and made available to the user or physician. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be described in more detail below based on exemplary embodiments with reference to the associated drawings.

[0041] In the attached picture:

[0042] Figure 1 An apparatus for determining the glucose concentration in the anterior chamber of a user's eye using a VCSEL is shown, wherein a first optical element having a mirror surface reflects laser light from the VCSEL,

[0043] Figure 2 A further apparatus for determining the glucose concentration in the anterior chamber of a user's eye using a VCSEL is shown, wherein a first optical element having a mirror surface reflects exiting light from the chamber,

[0044] Figure 3 An alternative apparatus for determining the glucose concentration in the anterior chamber of a user's eye using a VCSEL is shown, wherein a first optical element and a second optical element having respective mirror surfaces reflect the laser light and the exit light,

[0045] Figure 4 A further apparatus for determining the glucose concentration in the anterior chamber of a user's eye using a VCSEL is shown, wherein a third optical element having a quarter wave plate affects the laser light from the VCSEL, wherein reflection of the light in the anterior chamber is used,

[0046] Figure 5A further apparatus for determining the glucose concentration in the anterior chamber of a user's eye using a VCSEL is shown, wherein a fourth optical element having a liquid crystal module affects the laser light from the VCSEL,

[0047] Figure 6 A further apparatus for determining the glucose concentration in the anterior chamber of a user's eye using a VCSEL is shown, wherein an additional reference VCSEL emitting a reference laser is provided, and

[0048] Figure 7 It shows that the aforementioned Figures 1 to 6 An eyeglass unit of at least one of the devices in one of the figures. DETAILED DESCRIPTION

[0049] Figures 1 to 6 Different exemplary embodiments of an apparatus 10 for determining glucose concentration in an anterior chamber 12 of a user's eye 14 are shown. Each of the apparatuses 10 utilizes a VCSEL (Vertical Cavity Surface Emitting Laser) 11 that emits a laser 16 that is coupled into the anterior chamber 12 of the eye.

[0050] The VCSEL 11 has an emission region on its surface, from which laser light 16 is emitted from the VCSEL 11 .

[0051] Preferably, the wavelength of the laser light 16 is not lower than a limiting wavelength of >800 nm and not higher than an upper limiting wavelength of <1500 nm, so that reflection of the laser light 16 in the anterior chamber 12 is possible.

[0052] The device 10 enables non-invasive glucose measurement by means of measurements made on the user's eye 14 using a laser 16. Here, the fluid in the anterior chamber 12, which is composed of 98% water and contains glucose, albumin and ascorbic acid, is illuminated by the laser 16. Here, the laser 16 interacts with the glucose in the fluid in the chamber 12 because the glucose in the fluid in the anterior chamber 12 is chiral.

[0053] When the emitted and linearly polarized laser light 16 interacts with the chiral liquid, the field vector of the laser light rotates by a determined angular amount. The laser light then exits the anterior chamber 12 as exit light 20. The angular amount by which the polarization of the exit light 20 is rotated relative to the polarization of the laser light 16 entering the chamber is proportional to the concentration of glucose in the fluid in the anterior chamber.

[0054] The exit light 20 from the anterior chamber 12 penetrates into the VCSEL 11. In the cavity of the VCSEL 11, the exit light 20 interacts with the standing wave between the Bragg mirrors of the resonator of the VCSEL 11. This results in so-called self-mixing interference between the exit light 20 and the standing wave. The self-mixing interference can be analyzed with the aid of the analysis unit 13. In this regard, by analyzing the angular amount of rotation with the aid of the analysis unit 13 of the device 10, the glucose concentration in the anterior chamber and thus the blood sugar level can be inferred. Preferably, the VCSEL 11 has a polarization grating attached to the emission region from which the laser light 16 emerges and from which the exit light 20 re-enters the VCSEL 11. The intensity of the self-mixing interference is determined by the polarization grating of the VCSEL 11 according to the polarization of the exit light 20 penetrating into the VCSEL 11. This intensity can be used to determine the angular amount of polarization of the exit light 20.

[0055] Preferably, a photodiode is integrated in the VCSEL 11 to support the detection of the coupled outgoing light 20 in the VCSEL 11. An evaluation unit 13 is connected to the VCSEL 11 and the photodiode.

[0056] Figure 1 A device 10 is shown with a VCSEL 11, whose laser light 16 is transmitted from the VCSEL 11 along a first beam path 221 to a first optical element 241. The first optical element 241 has a mirror surface 26, by means of which the outgoing light 20 or the laser light 16 is affected in such a way that it is reflected. The reflected laser light 16 is transmitted from the first optical element 241 along a second beam path 222 to the anterior chamber 12 and enters the anterior chamber. In the anterior chamber 12, the laser light 16 interacts with the chiral liquid, and at least a portion of the laser light 16 is reflected by the lens of the eye and emerges from the anterior chamber 12 as outgoing light 20. Between the first beam path and the second beam path, the light is preferably reflected once and its propagation direction is changed.

[0057] After leaving the front eye chamber 12 , the exit light 20 is coupled back into the VCSEL 11 along a third beam path 223 extending from the eye chamber 12 to the VCSEL 11 .

[0058] Alternatively, laser light 16 may be first coupled into the anterior chamber 12 , and then the laser light is emitted from the chamber 12 as exit light 20 after being reflected in the chamber 12 or at the iris of the eye 14 , and is reflected at an optical element before entering the VCSEL.

[0059] In principle, the anterior eye chamber 12 is arranged between the first optical element 241 and the VCSEL 11 , wherein this may also be the case in the following exemplary embodiments.

[0060] exist Figure 2 In the embodiment of the present invention, the first optical element 24, i.e. the mirror on which the light first strikes, is arranged in the first beam path 221, after the anterior chamber 12. The mirror surface 26 is oriented perpendicular to the first beam path 221, so that the exit light 20 is reflected back into the anterior chamber along a second beam path 222 extending substantially parallel to the first beam path 221. This enables the polarization vector of the light to be even further rotated by a certain angular amount. After re-emitted from the anterior chamber 12, the exit light 20 re-enters the VCSEL 11, wherein the exit light 20 propagates along the second beam path 222 and thus propagates in the opposite direction to the laser 16.

[0061] Alternatively or in addition, the light 16 emitted from the VCSEL 11 can be focused into the anterior chamber by means of an optical element. For this purpose, an optical element in the form of a refractive lens and / or a diffractive lens and / or a lens made of a photonic metamaterial can be used, which is arranged between the VCSEL 16 and the chamber 12. Such an optical element can be attached directly to the emission area of ​​the VCSEL 11, thereby providing a single-piece VCSEL 11 with an attached optical element. This results in a high intensity in the anterior chamber 12 and a correspondingly strong interaction of the light 16 with the chiral liquid.

[0062] Such an optical element designed as a lens can be combined with all exemplary embodiments. Here, the lens can be arranged in both the beam path 221, 222, 223, 224 of the laser 16 and the beam path 221, 222, 223, 224 of the exit light 20, and can be combined with other optical elements 241, 242, 243, 244 in a way that ensures efficient utilization of the light from the VCSEL 11. In particular, the beam can be focused and / or collimated by the lens. In this regard, the beam can be focused into the anterior chamber 12 and / or onto the emission area.

[0063] The laser light 16 from the VCSEL 11 directly enters the anterior chamber 12, and the light emitted from the anterior chamber 12 directly hits the mirror surface 26 of the first optical element 24, is reflected from the mirror surface and is then coupled back into the anterior chamber 12. Then, the emitted light directly enters the VCSEL 11 from the chamber 12 to achieve self-mixing interference.

[0064] In this regard, the laser light 16 is preferably not reflected in the anterior chamber 12, but exits the anterior chamber 12 on the opposite side relative to the position where the laser light 16 enters the anterior chamber 12. The beam paths 221, 222 of the laser light 16 and the exit light 20 are collinear, wherein the laser light and the exit light extend along a straight axis perpendicular to the first optical element 241. The emission area on the VCSEL 11, the point where the laser light 16 enters the anterior chamber 12, and the point where the exit light 20 exits the anterior chamber 12 are located on a common axis.

[0065] In order to enable the laser light 16 or the outgoing light 20 to extend along the collinear first beam path 221 and the second beam path 222 , the anterior chamber 12 is arranged between the first optical element 241 and the VCSEL 11 .

[0066] Figure 3 An exemplary embodiment of the device 10 is shown in which the anterior chamber 12 is positioned between the first optical element 241 and the second optical element 242 .

[0067] The laser light 16 from the VCSEL 11 propagates along the first beam path 221 directly to the second optical element 242, and is reflected at the mirror surface 26 at the second optical element 242, which is oriented so that the second beam path 222 of the laser light 16 passes through the anterior eye chamber 12. Therefore, the laser light 16 reflected at the second optical element 242 is coupled into the anterior eye chamber 12.

[0068] Preferably, the coupled laser light 16 passes through the anterior chamber 12 without being reflected in the anterior chamber 12, so that the exit light 20 exits at the opposite side of the chamber 12. The second beam path 222 passes through the anterior chamber 12 and is reflected at the first optical element 241.

[0069] After being reflected at the first optical element 241, the exit light 20 propagates backward along the third beam path 223 toward the second optical element 242. In this regard, the exit light 20 reflected at the first optical element 241 is not coupled into the anterior eye chamber 12, but is guided through the anterior eye chamber. For this purpose, the mirror surface 26 of the first optical element 241 is tilted relative to the second beam path 222, so that the mirror surface 26 is not oriented perpendicularly to the second beam path 222.

[0070] according to Figure 3 In the exemplary embodiment of the present invention, the first beam path 221 and the third beam path 223 cross each other.

[0071] The exit light is reflected by the second optical element 241 and propagates to the VCSEL 11 along the fourth beam path 224. Then, the exit light is coupled into the VCSEL 11 to achieve self-mixing interference.

[0072] Figure 4 A further exemplary embodiment of the device 10 is shown, in which an optical element is provided as a filter for the outgoing light 20. The filter represents a third optical element 243, which produces a phase delay of a quarter wavelength when the light passes through the third optical element. Here, the third optical element 243 is positioned between the anterior chamber 12 and the VCSEL 11 in the first beam path 221 of the laser light 16 from the VCSEL 11 and the second beam path 222 of the outgoing light 20.

[0073] The third optical element 243 is a quarter wave plate. If the laser light 16 from the VCSEL 11 passes through the quarter wave plate and the linear polarization of the laser light 16 is oriented in the direction of the optical axis of the quarter wave plate, the laser light 16 maintains the linear polarization.

[0074] The exit light 20 rotated by a certain angular amount relative to the laser light 16 from the VCSEL 11 by the chiral liquid in the anterior chamber 12 is also linearly polarized. However, due to the angular amount, the polarization is also tilted relative to the optical axis of the quarter wave plate. If the exit light 20 now strikes the quarter wave plate with a polarization tilted by a certain angular amount, the exit light 20 is circularly polarized. Therefore, since the laser light 16 from the VCSEL 11 and the exit light 20 from the anterior chamber 12 exhibit different polarizations, the polarization can be used to distinguish the exit light 20 from the scattered light or laser light 16.

[0075] exist Figure 5 , a device 10 is shown having a fourth optical element 244, which is arranged to modulate the laser light 16 or the outgoing light 20. The fourth optical element 244 has a liquid crystal module, which is connected to the driver device 30. The liquid crystal module polarizes the laser light 16 before it enters the anterior chamber 12.

[0076] The liquid crystal module is controlled by the driver device 30 in such a way that it causes the laser light 16 to enter at least two different polarization modes or polarization directions. For example, two different linear polarization directions may be set. Alternatively, more than two polarization directions may be set.

[0077] For example, the polarization may be adjusted periodically by the actuator device 30 .

[0078] In addition, a third optical element 243 may be arranged in the beam paths 221, 222 of the laser light 16 or the outgoing light 20. For example, the laser light 16 may be tilted once in the direction of the optical axis of the third optical element 243, which is a quarter wave plate, and tilted once by a certain angle relative to the optical axis of the third optical element 243. Since circular polarization or modified linear polarization can be generated by tilting the polarization axis relative to the optical axis of the quarter wave plate, the third optical element 243 may be used to distinguish between two polarization types or directions.

[0079] In particular, the frequency of setting the different polarization modes is higher than the frequency of average human eye movement, so that the polarization mode changes at least once when the eye is stationary. Therefore, the glucose concentration in the anterior chamber 12 can be measured by means of the laser 16 modulated by the fourth optical element 244, wherein the sensitivity of the laser 16 can be adjusted with respect to the chiral liquid in the anterior chamber 12.

[0080] LCD modules can also be Figures 1 to 6 In any of the further embodiments of the present invention, the liquid crystal module may be arranged in the beam path of the outgoing light 20 or the laser light 16. In addition, a plurality of liquid crystal modules may be used.

[0081] Alternatively or in addition, the light may already be modulated in the VCSEL 11. For example, a piezoelectric element may be attached to the VCSEL 11, which generates a mechanical tension in the VCSEL 11 having a corresponding orientation relative to the crystal orientation of the semiconductor material of the VCSEL 11, so that the laser light 16 leaves the VCSEL 11 with a desired polarization. The piezoelectric element may be controlled by a driver device, for example periodically.

[0082] As a further alternative or in addition, a heating element may be provided which, by heating the semiconductor material, generates a mechanical tension in the semiconductor material which influences the polarization of the laser light 16 , like a piezoelectric element.

[0083] Figure 6 A further exemplary embodiment is shown in which, in addition to the VCSEL 11 , a reference VCSEL 34 is provided which emits a reference laser light 28 which propagates along a reference beam path 311 to the eye 14 .

[0084] The polarization of the reference laser 28 is selected so that it interacts less with the chiral fluid in the anterior chamber 12 than the laser 16 of the VCSEL 11 of the device 10. Preferably, the reference laser 28 is completely uniformly circularly polarized when coupled into the anterior chamber 12, since circularly polarized light is not rotated by interaction with fluid in the eye.

[0085] In order to circularly polarize the reference laser light 28, the reference laser light can pass through a reference optical element 245 which is a quarter wave plate, wherein the reference laser light 28 from the reference VCSEL 34 is tilted by an angle of, for example, 45° relative to the optical axis of the quarter wave plate. The circularly polarized reference laser light 28 is reflected as a reference exit light 33, which is also circularly polarized. The reference exit light 33 is linearly polarized again by the reference optical element 245. In this regard, the reference exit light can achieve self-mixing interference in the reference VCSEL 34. This enables conclusions about eye movement and / or glucose concentration to be drawn in conjunction with the VCSEL 11.

[0086] Preferably, the reference optical element 245 and the optical element 243 may be integrated in a single component in an integral manner.

[0087] By way of example, Figure 6 VCSEL 11 in Figure 4 The laser 16 of the VCSEL 11 and the reference laser 28 preferably propagate along almost collinear beam paths 221, 311. Similarly, the exit light 20 and the reference exit light 33 may extend along almost collinear beam paths 222, 312. For example, a VCSEL array having at least two emission regions may be used, wherein at least one emission region is provided for the reference laser 28 and another emission region is provided for the laser 16.

[0088] In another alternative or additional embodiment, by using a corresponding optical system, the reference laser light 28 of the reference VCSEL 34 may propagate along a beam path colinearly with the laser light 16 of the VCSEL 11. For example, the optical system may have an optical fiber.

[0089] Figure 7 An eyeglass unit 36 ​​is shown which is arranged to be worn by a user and has an eyeglass frame 38. Figures 1 to 6 In this case, the optical elements 241, 242, 243, 244, 245 may be arranged opposite to the VCSEL 11 in the glasses frame 38 relative to the glasses lens 40.

[0090] For example, the glasses unit 36 ​​may be a pair of data glasses, virtual reality glasses, augmented reality glasses or conventional vision aid glasses. In addition, a battery for powering the device and a control system of the device 10 may be attached to the glasses unit 36.

[0091] All described exemplary embodiments of the device 10 can determine the glucose concentration at regular time intervals. After a time interval in which no measurement is performed, the glucose measurement is started. The time intervals can have the same length, or be individually programmed. For example, the time intervals can be selected so that glucose measurements are performed at mealtimes, because at this time there is a high probability that the blood sugar level will rise due to technical reasons as a result of food intake.

[0092] Blood glucose levels may also be measured during physical activity, such as sports.

[0093] At the same time, the control system of the device can indicate to the user the glucose level present in the anterior chamber 12 and accordingly suggest an insulin dose or glucose intake. The suggestion can be displayed on the eyeglass lens 40, in the eye 14 and / or on a computer (e.g., a smart phone).

[0094] A time record may be created showing the history of glucose concentration over time in the anterior chamber 12. For example, the record is available in digital form and may be read from the device via radio or a physical interface such as USB.

[0095] For example, the record may be transmitted from the device to a computing device such as a smartphone or to the cloud where it is further processed and made available to the user or physician.

[0096] Reference numerals list

[0097] 10 Installation

[0098] 11VCSEL

[0099] 12 Eye Room

[0100] 13 Analysis Unit

[0101] 14 Eyes

[0102] 16 Laser

[0103] 20 emerging light

[0104] 221 First beam path

[0105] 222 Second beam path

[0106] 223 Third beam path

[0107] 224 Fourth beam path

[0108] 241 First Optical Element

[0109] 242 Second optical element

[0110] 243 Third Optical Element

[0111] 244 Fourth Optical Element

[0112] 26 Mirror surface

[0113] 28 Reference laser

[0114] 30 Driver device Reference beam path of 311 reference laser 312 Reference beam path of reference output light 33 Reference output light 34 Reference VCSEL

[0115] 36 Glasses Unit

[0116] 38 glasses frame 40 glasses lenses

Claims

1. A device (10) for determining the glucose concentration in the anterior chamber (12) of an eye (14) of a user, the device comprising: a VCSEL (11) emitting laser light (16); and optical elements (241, 242, 243, 244) for influencing the laser light (16) and / or the exiting light (20), wherein: The VCSEL (11) and the optical elements (241, 242, 243, 244) are designed so that the laser light (16) enters the anterior chamber (12), wherein the outgoing light (20) from the anterior chamber (12) penetrates into the VCSEL (11), and the glucose concentration can be determined by analyzing the self-mixing interference thus generated in the VCSEL (11) through an analysis unit (13).

2. The device (10) according to claim 1, characterized in that The first optical element (241) has a mirror surface (26), wherein the mirror surface (26) is arranged in the beam path of the outgoing light (20) or the laser (16) so that the outgoing light (20) can be reflected on the mirror surface (26).

3. The device (10) according to claim 1 or 2, characterized in that The anterior eye chamber (12) is positioned between the VCSEL (11) and the first optical element (241) along the beam path (221, 222, 223, 224).

4. The device (10) according to claim 3, characterized in that The laser light (16) from the VCSEL (11) preferably enters the anterior eye chamber (12) directly, and the exit light (20) is directed onto the mirror surface (26).

5. The device (10) according to any one of claims 2 to 4, characterized in that The anterior eye chamber (12) is arranged between the first optical element (241) and the VCSEL (11), wherein the mirror surface (26) is preferably oriented perpendicular to the beam path (221, 222, 223, 224) of the exit light (20) so that the exit light (20) can be reflected back into the anterior eye chamber (12).

6. The device (10) according to any one of the preceding claims, characterized in that The anterior chamber (12) is positioned between the first and second optical elements (242) such that the beam path (221, 222, 223, 224) of the laser (16) extends through the anterior chamber (12).

7. The device (10) according to claim 6, characterized in that The beam path (221, 222, 223, 224) of the laser light (16) from the VCSEL (11) extends directly to the second optical element (242).

8. The device (10) according to claim 6 or 7, characterized in that The beam paths (221, 222, 223, 224) of the lasers (16) intersect at least once.

9. The device (10) according to any one of claims 6 to 8, characterized in that The beam path (221, 222, 223, 224) of the outgoing light (20) extends from the first optical element to the second optical element (242).

10. The device (10) according to any one of the preceding claims, characterized in that A third optical element (243) is provided, which generates a phase delay of a quarter wavelength when the laser light (16) passes through.

11. The device (10) according to claim 10, characterized in that The third optical element (243) is positioned between the anterior chamber (12) and the VCSEL (11) in a beam path of the laser light (16) and the exit light (20) from the VCSEL (11).

12. The device (10) according to any one of the preceding claims, characterized in that A fourth optical element (244) is provided, the fourth optical element having a liquid crystal module, the liquid crystal module affecting the polarization direction of the laser light (16) before the laser light (16) enters the anterior eye chamber (12), wherein the liquid module is connected to a driver device (30).

13. The device (10) according to any one of the preceding claims, characterized in that In addition to the VCSEL (11), a reference VCSEL (34) is provided, which emits a reference laser light (28) which propagates along a reference beam path (311) to the eye (14).

14. The device (10) according to claim 13, characterized in that The reference laser light (28) and the laser light (16) propagate colinearly with each other.

15. The device (10) according to any one of the preceding claims, characterized in that An optical element is provided, wherein the optical element is a refractive lens and / or a diffractive lens and / or a lens made of photonic metamaterial, and the optical element is arranged between the VCSEL (11) and the anterior eye chamber (12).

16. An eyeglass unit (36) to be worn by a user, the eyeglass unit having a device (10) according to any of the preceding claims, enabling a user of the eyeglass unit (36) to determine his own blood glucose level.

17. A method for determining the glucose concentration in the anterior chamber (12) of a user's eye (14) using the device (10) according to any one of the preceding claims, the method comprising the steps of: - emitting said laser light (16), - causing the laser light (16) to enter and leave the anterior chamber (12), - receiving the laser light (16) with the VCSEL (11), - generating self-mixing interference in the VCSEL (11), - analyzing the self-mixing interferometry with respect to the glucose concentration in the anterior chamber (12), - determining said glucose concentration.

18. The method according to claim 17, characterized in that The determination of the glucose concentration is performed regularly at specific time intervals, so that a chronological record of the glucose concentration at different points in time is created and stored in a memory of the device (10).

19. The method according to claim 18, characterized in that The record is sent from the device (10) via radio to a computing device such as a smartphone or the cloud.

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