Optical microscopy system for intraocular pressure measurement

Abstract

The present invention relates to the technical field of optical measurement. Provided are an optical microscopy system for intraocular pressure measurement. The optical microscopy system comprises a spatial optical sensing unit, a light transmission unit, an intraocular pressure sensor, a spectrum collection unit and a spectrum demodulation unit, wherein the spatial optical sensing unit is connected to the spectrum collection unit; the spectrum collection unit is connected to the spectrum demodulation unit by means of a first transmission link; a Fabry-Perot microcavity is provided on the intraocular pressure sensor; broadband light emitted by the spatial optical sensing unit is vertically incident to the Fabry-Perot microcavity by means of the light transmission unit, so as to obtain interference broadband light; the interference broadband light is transmitted to the spectrum collection unit; the spectrum collection unit converts the interference broadband light into a digital spectrum and then transmits the digital spectrum to the spectrum demodulation unit; and the spectrum demodulation unit acquires an intraocular pressure according to the digital spectrum. By means of the cooperation of a spatial optical sensing unit, a light transmission unit and an intraocular pressure sensor, the present invention completes the incidence of broadband light and the reception of interference broadband light, thereby reducing optical elements.

Description

An optical microscope system for measuring intraocular pressure Technical Field

[0001] The present invention relates to the technical field of optical measurement, and in particular to an optical microscope system for measuring intraocular pressure. Background Art

[0002] Glaucoma is one of the three major causes of blindness. It carries significant risks and is the world's leading irreversible cause of blindness. Intraocular pressure (IOP) refers to the pressure exerted on the eyeball by the contents of the eye. Normally, it ranges from 10 to 21 mmHg. High IOP is considered a significant risk factor for glaucoma. Therefore, IOP is a crucial indicator in clinical practice for determining treatment goals and assessing treatment efficacy and prognosis.

[0003] Currently, the primary method for measuring intraocular pressure in clinical practice is to measure the patient's immediate intraocular pressure using instruments, including applanation tonometers and air jet tonometers. Applanation tonometers are currently considered the "gold standard" for measuring intraocular pressure, but this method is complex and has disadvantages such as requiring topical anesthesia before measurement, requiring sodium fluorescein to be dripped onto the cornea during measurement, and the measurement value being affected by the central corneal thickness. Compared to applanation tonometers, air jet tonometers simplify the intraocular pressure measurement process and do not require topical anesthesia or sodium fluorescein. However, air jet tonometers also have many problems, including the impact of airflow that can cause eye discomfort in patients and the expensive and non-portable nature of the instrument.

[0004] In addition, there are many studies on miniature intraocular pressure sensors based on different principles. The common characteristics of these studies are: 1. The sensor is separated from the detection equipment, and the sensing method is non-contact; 2. The sensor area and volume are very small, ranging from hundreds of microns to a few millimeters; 3. The sensor is in contact with the eye structure and is either attached to the eyeball or implanted inside the eyeball.

[0005] Proposed miniature intraocular pressure sensors can be categorized by sensing principle into three main types: electrical, microfluidic, and optical. Chen et al. designed a contact lens-based intraocular pressure sensor based on capacitance-pressure sensitivity. The frequency of the LC oscillator formed by the capacitor and inductor changes with pressure, and the reading device is a large network analyzer. Agaoglu et al. used a microfluidic chip to measure intraocular pressure. An artificial lens with an integrated microfluidic chip was implanted into the eye using cataract surgery techniques. Fluctuations in intraocular pressure cause displacement of the liquid-air interface of the artificial lens, and monitoring this interface position provides the intraocular pressure reading. Limited by circuit structure and materials, electrical sensing is difficult to achieve submillimeter dimensions, and the reading device is bulky and expensive. Microfluidic sensing, limited by stringent airtightness requirements and the indirect sensing principle of photographic reading, presents a bottleneck in miniaturization. Optical sensors, however, are generally smaller than electrical and microfluidic sensors, and therefore have become a major research direction for implantable sensors.

[0006] Existing optical measurement solutions are all based on the Fabry–Pérot interferometer structure. Lee's team used silicon nitride for a flexible sensing membrane and silicon for the outer shell, reducing the sensor size to approximately 1mm and achieving a detection accuracy of 1.3mmHg. Kim's team further optimized Lee's work and incorporated artificial intelligence (ANN) into the demodulation algorithm, increasing the accuracy to 0.1mmHg. Both sensors are millimeter-sized and manufactured using etching and assembly processes. This poses significant challenges for mass production and minimally invasive implantation. Furthermore, the aforementioned team used a slit lamp, a professional ophthalmic testing device, as a base, modified and expanded to include a desktop broadband light source input interface and an output interface to a large spectrometer. The overall system was complex, lacking portability and high cost.

[0007] In view of this, it is particularly important to provide a non-contact optical microscopy system with a simple structure. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: in order to solve the problem of overall redundancy of optical detection equipment used for intraocular pressure measurement in the prior art, the present invention provides an optical microscope system for intraocular pressure measurement. The optical microscope system optimizes the optical path, reduces optical components, simplifies the structure of the optical microscope system, and solves the problem of overall redundancy of optical detection equipment used for intraocular pressure measurement in the prior art.

[0009] The technical solution adopted by the present invention to solve its technical problems is: an optical microscopy system for measuring intraocular pressure, comprising a spatial optical sensing unit, a light transmission unit, an intraocular pressure sensor, a spectrum acquisition unit and a spectrum demodulation unit; wherein the spatial optical sensing unit is connected to the spectrum acquisition unit; the spectrum acquisition unit and the spectrum demodulation unit are connected through a transmission link; a Fabry-Perot microcavity is provided on the intraocular pressure sensor; the broadband light emitted by the spatial optical sensing unit is vertically incident on the Fabry-Perot microcavity through the light transmission unit to obtain interference broadband light; the interference broadband light passes through the light transmission unit and the spatial optical sensing unit and is transmitted to the spectrum acquisition unit; the spectrum acquisition unit converts the interference broadband light into a digital spectrum and transmits the digital spectrum to the spectrum demodulation unit; the spectrum demodulation unit obtains intraocular pressure based on the digital spectrum.

[0010] Optionally, the spatial optical sensing unit includes a broadband light source, a fiber optic circulator and a fiber optic collimator; wherein the broadband light source and the fiber optic circulator, the fiber optic circulator and the fiber optic collimator, and the fiber optic circulator and the spectrum acquisition device are all connected via optical fibers; the broadband light source is used to emit the broadband light; the broadband light passes through the fiber optic circulator and the fiber optic collimator in sequence and is input into the light transmission unit; the interference broadband light passes through the light transmission unit, the fiber optic collimator, and the fiber optic circulator in sequence and is then delivered to the spectrum acquisition unit.

[0011] Optionally, the wavelength range of the broadband light is 750nm-950nm.

[0012] Optionally, it also includes a microscopic imaging positioning unit; the microscopic imaging positioning unit is connected to the spectral demodulation unit via a second transmission link; the indicator light emitted by the microscopic imaging positioning unit is incident on the Fabry-Perot microcavity through the light transmission unit to obtain reflected indicator light; the reflected indicator light is received and imaged by the microscopic imaging positioning unit after passing through the light transmission unit to obtain a real-time image, and the real-time image is transmitted to the spectral demodulation unit.

[0013] Optionally, the microscopic imaging positioning unit includes a CCD camera and an indicator light source; the indicator light source is used to emit the indicator light; and the CCD camera is signal-connected to the spectrum demodulation unit.

[0014] Optionally, the light transmission unit includes a lens group and an objective lens sequentially arranged along the light path.

[0015] Optionally, the spectrum acquisition unit includes an optical dispersion conversion module, an embedded module and a power driving module; wherein the power driving module supplies power to the optical dispersion conversion module under the control of the embedded module; the optical dispersion conversion module converts the interfering broadband light of different wavelengths into an electrical signal through a diffraction effect, and transmits the electrical signal to the embedded module; the embedded module is used to digitize the electrical signal to obtain the digital spectrum.

[0016] Optionally, the spectrum demodulation unit includes at least one central processing unit.

[0017] Optionally, the spectral demodulation unit obtains the intraocular pressure based on the digital spectrum, including the following steps: S1: determining the position of the optical microscope system; S2: reading the digital spectrum to obtain original spectral data; S3: extracting the maximum value of the original spectral data, comparing the maximum value with a preset threshold, and judging whether the maximum value is not less than the preset threshold, if so, proceeding to step S4, otherwise proceeding to step S1; S4: performing spectral interpolation processing on the original spectral data, and performing FFT filtering to restore the spectral data of the interference broadband light; S5: using a peak-finding algorithm to de-peak the spectral data of the interference broadband light, and obtain the central wavelength position of the spectral data of the interference broadband light; S6: obtaining the intraocular pressure through the central wavelength position.

[0018] Optionally, the preset threshold is 50% of the mirror reflected light intensity when the broadband light is vertically incident on the plane reflector.

[0019] The beneficial effects of the present invention are as follows: the optical microscopy system for intraocular pressure measurement provided by the present invention achieves the incidence of broadband light and the reception of interference broadband light through the cooperation of a spatial optical sensing unit, a light transmission unit and an intraocular pressure sensor, and measures intraocular pressure based on a Fabry–Pérot interference structure. While ensuring the accuracy of the intraocular pressure measurement results, it reduces the number of optical components, simplifies the structure of the optical microscopy system, and solves the problem of overall redundancy of optical detection equipment used for intraocular pressure measurement in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and examples.

[0021] FIG1 is a schematic structural diagram of an optical microscope system for measuring intraocular pressure in the present invention.

[0022] FIG2 is a schematic structural diagram of the spectrum acquisition unit 4 in the present invention.

[0023] FIG3 is a schematic diagram of a flow chart of spectrum demodulation performed by the spectrum demodulation unit in the present invention.

[0024] FIG4 is a diagram of original spectrum data read by a demodulation system in a specific embodiment of the present invention.

[0025] FIG5 is a diagram of interference spectrum data restored by a demodulation system in a specific embodiment of the present invention.

[0026] FIG6 is a diagram of interference spectrum data at different pressures in a specific embodiment of the present invention.

[0027] FIG7 is a linear fitting result of the central wavelength corresponding to the interference spectrum peak and the applied pressure.

[0028] In the figure: 1-spatial optical sensing unit; 11-broadband light source; 12-fiber circulator; 13-fiber collimator; 2-light transmission unit; 21-lens group; 22-objective lens; 3-intraocular pressure sensor; 4-spectral acquisition unit; 41-light dispersion conversion module; 42-embedded module; 43-power drive module; 5-spectral demodulation unit; 6-microscopic imaging positioning unit; 61-CCD camera; 62-indicator light source; 7-transmission link 1; 8-transmission link 2. Implementation Method

[0029] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] In order to solve the problem of redundant overall system of optical detection equipment for intraocular pressure measurement in the prior art, the present invention provides an optical microscopy system for intraocular pressure measurement, as shown in FIG1 , the optical microscopy system includes a spatial optical sensing unit 1, a light transmission unit 2, an intraocular pressure sensor 3, a spectrum acquisition unit 4 and a spectrum demodulation unit 5; wherein the spatial optical sensing unit 1 is connected to the spectrum acquisition unit 4 via an optical fiber; the spectrum acquisition unit 4 is connected to the spectrum demodulation unit 5 via a transmission link 7, which is a transmission link for digital electrical signals, and the transmission implementation method can be a wired transmission technology or a wireless transmission technology; it is worth noting that the wired transmission technology includes but is not limited to serial port, USB, Ethernet, CAN, HDMI, DisplayPort, etc. ort, etc.; wireless transmission technologies include but are not limited to WIFI, Bluetooth, 2.4G, NFC, etc.; a Fabry-Perot microcavity is provided on the intraocular pressure sensor 3; during operation, the broadband light emitted by the spatial optical sensing unit 1 is vertically incident on the Fabry-Perot microcavity, i.e., the FP resonant cavity, on the intraocular pressure sensor 3 through the light transmission unit 2, enters the cavity of the Fabry-Perot microcavity, is reflected by multiple surfaces and interferes, and obtains interference broadband light; the obtained interference broadband light passes through the light transmission unit 2 and the spatial optical sensing unit 1 in turn and is transmitted to the spectrum acquisition unit 4; the spectrum acquisition unit 4 converts the interference broadband light into a digital spectrum, and then transmits the digital spectrum to the spectrum demodulation unit 5; the spectrum demodulation unit 5 obtains the liquid environment pressure outside the Fabry-Perot microcavity on the intraocular pressure sensor 3, i.e., the intraocular pressure, according to the digital spectrum.

[0032] The optical microscopy system for intraocular pressure measurement provided by the present invention achieves the incidence of broadband light and the reception of interfering broadband light through the cooperation of a spatial optical sensing unit 1, a light transmission unit 2, and an intraocular pressure sensor 3. It measures intraocular pressure based on a Fabry–Pérot interferometer structure. While ensuring the accuracy of the intraocular pressure measurement results, it reduces the number of optical components, simplifies the structure of the optical microscopy system, and solves the problem of overall redundancy of optical detection equipment used for intraocular pressure measurement in the prior art.

[0033] The intraocular pressure sensor 3 of the present invention is preferably manufactured using two-photon femtosecond laser 3D printing technology. Its structure contains an optical Fabry–Pérot interferometer cavity, or Fabry–Pérot microcavity. The outer reflective surface of the cavity is a thin film sensitive to external pressure changes, while the inner reflective surface of the cavity is a rigid structure that is unaffected by external pressure. By using two-photon femtosecond laser 3D printing technology, the precision manufacturing of Fabry–Pérot structure intraocular pressure sensors sensitive to pressure changes can be achieved in batches at submillimeter scale. The present invention preferably adopts the outer reflective surface of the FP resonant cavity, or Fabry–Pérot microcavity, as opposed to and parallel to the inner reflective surface. This intraocular pressure sensor 3 can be an existing intraocular pressure sensor with a Fabry–Pérot microcavity, such as the intraocular pressure sensor described in patent application number 2022104328698.

[0034] The spatial optical sensing unit 1 in the present invention includes a broadband light source 11, a fiber circulator 12, and a fiber collimator 13; the broadband light source 11 and the fiber circulator 12, the fiber circulator 12 and the fiber collimator 13, and the fiber circulator 12 and the spectrum acquisition device 4 are all connected by optical fibers; the broadband light source 11 is used to emit broadband light; the broadband light is sequentially input into the light transmission unit 2 through the fiber circulator 12 and the fiber collimator 13; the interference broadband light is sequentially transmitted through the light transmission unit 2, the fiber collimator 13, and the fiber circulator 12 before being transmitted to the spectrum acquisition unit 4.

[0035] Specifically, the broadband light emitted by the broadband light source 11 is input to the first port of the fiber circulator 12 through the optical fiber, and then output from the second port of the fiber circulator 12, and input to the fiber collimator 13 through the optical fiber; the fiber collimator 13 is fixed at a position perpendicular to the optical axis of the light transmission unit 2, so that the broadband light is collimated by the fiber collimator 13, and then vertically incident on the Fabry-Perot microcavity of the intraocular pressure sensor 3 through the light transmission unit 2. The broadband light enters the cavity of the Fabry-Perot microcavity, is reflected by multiple surfaces and interferes, and obtains interfering broadband light; the obtained interfering broadband light passes through the light transmission unit 2, enters the fiber collimator 13 and the fiber circulator 12 in sequence, and is then output from the third port of the fiber circulator 12 and transmitted to the spectrum acquisition unit 4 through the optical fiber.

[0036] The optical microscopy system for intraocular pressure measurement provided by the present invention comprises a broadband light source 11, a fiber circulator 12, a fiber collimator 13, a light transmission unit 2, and a Fabry-Perot microcavity of an intraocular pressure sensor 3, forming a broadband light transmission path. Furthermore, the Fabry-Perot microcavity of the intraocular pressure sensor 3, the light transmission unit 2, the fiber collimator 13, the fiber circulator 12, and a spectrum acquisition unit 4 form an interferometric broadband light transmission path. This allows for the transmission of both broadband light and interferometric broadband light using a relatively small number of components.

[0037] The present invention preferably uses broadband light with a wavelength range of 750nm-950nm. Light in this wavelength range is invisible to the human eye, does not cause discomfort to the patient, and does not induce protective actions such as blinking or eye movement. Furthermore, light in this wavelength range is not absorbed by the cornea and has good penetrability, allowing most of the energy to reach the intraocular pressure sensor 3 directly. It is worth noting that broadband light excitation can be achieved using, but is not limited to, LED semiconductor infrared light sources, thermal radiation infrared light sources, gas discharge infrared light sources, laser infrared light sources, liquid crystal infrared light sources, and the like.

[0038] Furthermore, the present invention preferably includes a microscopic imaging positioning unit 6 for measuring intraocular pressure, wherein the microscopic imaging positioning unit 6 is connected to the spectral demodulation unit 5 via a transmission link 2 8, which is a transmission link for digital signals, and the transmission implementation method may be a wired transmission technology or a wireless transmission technology; it is worth noting that wired transmission technologies include but are not limited to serial ports, USB, Ethernet, CAN, HDMI, DisplayPort, etc.; wireless transmission technologies include but are not limited to WIFI, Bluetooth, 2.4G, NFC, etc.; during operation, the indicator light emitted by the microscopic imaging positioning unit 6 is incident on the Fabry-Perot microcavity of the intraocular pressure sensor 3 through the light transmission unit 2 to obtain reflected indicator light; after the reflected indicator light passes through the light transmission unit 2, it is received and imaged by the microscopic imaging positioning unit 6 to obtain a real-time image, and the real-time image is transmitted to the spectral demodulation unit 5, and the position of the intraocular pressure sensor 3 is monitored by the spectral demodulation unit 5, so as to monitor the position where the indicator light is irradiated on the intraocular pressure sensor 3.

[0039] Furthermore, the present invention preferably has the same transmission optical path of the indicator light and the broadband light in the light transmission unit 2, that is, the indicator light and the broadband light in the light transmission unit 2 are in the same straight line in space, thereby ensuring that the incident positions of the indicator light and the broadband light on the intraocular pressure sensor 3 are the same, and then the incident position of the broadband light on the intraocular pressure sensor 3 can be monitored by monitoring the incident position of the indicator light on the intraocular pressure sensor 3, thereby facilitating the operator to adjust the position of the spatial optical sensing unit 1 according to the real-time image obtained.

[0040] Furthermore, it is preferred to display the real-time image on a corresponding visual screen so as to intuitively monitor the position of the intraocular pressure sensor 3 .

[0041] Specifically, the present invention preferably comprises a microscopic imaging positioning unit 6 including a CCD camera 61 and an indicator light source 62; the indicator light source 62 is used to emit indicator light; wherein the indicator light source 62 is fixed at a position perpendicular to the optical axis of the light transmission unit 2, and the emission direction of the indicator light emitted by the indicator light source 62 is perpendicular to the optical axis of the light transmission unit 2; the CCD camera 61 is coaxially arranged with the light transmission unit 2; and the CCD camera 61 is signal-connected to the spectral demodulation unit 5.

[0042] During operation, the indicator light emitted by the indicator light source 62 passes through the light transmission unit 2 and is vertically incident on the Fabry-Perot microcavity of the intraocular pressure sensor 3, and then reflected to form reflected indicator light; the reflected indicator light passes through the light transmission unit 2 and is received and imaged by the CCD camera 61 to obtain a real-time image; by transmitting the real-time image to the spectral demodulation unit 5, the position of the intraocular pressure sensor 3 is monitored.

[0043] In the present invention, the indicator light source 62, the light transmission unit 2, and the Fabry-Perot microcavity of the intraocular pressure sensor 3 constitute the transmission route of the indicator light, and the Fabry-Perot microcavity, the light transmission unit 2, and the CCD camera constitute the transmission route of the reflected indicator light, thereby realizing the monitoring of the position of the intraocular pressure sensor 3.

[0044] As shown in Figure 1, the broadband light and interference broadband light, as well as the indicator light and reflected indicator light in the present invention, share a light transmission unit 2 for light transmission. Without adding any additional optical components, the position of the intraocular pressure sensor 3 and the measurement of the intraocular pressure can be monitored simultaneously, which can improve the accuracy of intraocular pressure measurement without adding any optical components, thereby helping to further simplify the structure of the optical microscope system.

[0045] To facilitate the transmission of light, the light transmission unit 2 in the present invention includes a lens group 21 and an objective lens 22 arranged in sequence along the optical path; the lens group 21 and the objective lens 22 form a coaxial structure; the lens group 21 can include two or more lenses, and the two or more lenses respectively reflect or transmit the indicator light and the broadband light to achieve the transmission of broadband light, interference broadband light, indicator light and reflected indicator light; the lenses in the lens group 21 can be treated by coating or other methods to make them selectively transparent, that is, the same lens can reflect light in certain specific wavelength ranges and transmit light in certain specific wavelength ranges, so that the indicator light, reflected indicator light, broadband light and interference broadband light can be simultaneously transmitted through the lens group 21; and the reflectivity and transmittance of each lens for light in different wavelength ranges can be selected according to the requirements of the optical path; or, each lens can also be set to reflect or transmit light in different wavelength ranges in different areas.

[0046] Specifically, after the indicator light enters the lens group 21, it is reflected and incident on the objective lens 22. The objective lens 22 focuses the indicator light onto the surface of the intraocular pressure sensor 3; the indicator light is reflected to form reflected indicator light; the objective lens 22 collects the reflected indicator light, and the reflected indicator light is received by the CCD camera 61 and imaged after passing through the lens group 21.

[0047] After the broadband light enters the lens group 21, it is reflected and incident on the objective lens 22. The objective lens 22 focuses the broadband light onto the Fabry-Perot microcavity on the intraocular pressure sensor 3 to generate interfering broadband light; the objective lens 22 collects the interfering broadband light, and the interfering broadband light passes through the lens group 21 and is input into the fiber collimator 13.

[0048] In the present invention, the objective lens 22 preferably focuses the indicator light and the broadband light vertically to the same point on the intraocular pressure sensor 3 at the same time, and collects the returned reflected indicator light and the interfering broadband light at the same time.

[0049] The present invention preferably configures the spatial optical sensing unit 1, light transmission unit 2, and microscopic imaging positioning unit 6 as a single unit, supported by a multi-dimensional translation stage. This stage allows for precise adjustment of the position and angle of the focused light spot of the objective lens 22 on the intraocular pressure sensor 3. It is worth noting that "multi-dimensional" includes, but is not limited to, front-to-back, left-to-right, up-and-down, pitch, and yaw. Adjustment methods include, but are not limited to, manual, electric, pneumatic, and hydraulic adjustments.

[0050] The present invention integrates the microscopic imaging positioning unit 6, the spatial optical sensing unit 1 and the light transmission unit 2 into one, so that the optical microscopic system for intraocular pressure measurement has good structural stability, high sensing reliability, small size, high portability and low cost.

[0051] Furthermore, the present invention preferably integrates the broadband light source 11, the optical fiber circulator 12, the spectrum acquisition unit 4 and the driving circuit of the indicator light source 62 into one chassis. The whole machine is powered by an external power supply or an internal battery, and the two power supply modes can be switched at will.

[0052] As shown in Figure 2, the spectrum acquisition unit 4 in the present invention includes an optical dispersion conversion module 41, an embedded module 42 and a power driving module 43; wherein the power driving module 43 supplies power to the optical dispersion conversion module 41 under the control of the embedded module 42; the optical dispersion conversion module 41 converts interfering broadband light of different wavelengths into electrical signals through the diffraction effect, and transmits the electrical signals to the embedded module 42; the embedded module 42 is used to digitize the electrical signals to obtain a digital spectrum.

[0053] Specifically, the power driving module 43 is controlled by the embedded module 42 and is used to supply power to the optical dispersion conversion module 41, and realizes the photoelectric conversion of different speeds of the optical dispersion conversion module 41 by adjusting the power supply frequency; the optical dispersion conversion module 41 spatially distinguishes light of different wavelengths through the diffraction effect, and then converts light of different wavelengths into electrical signals of corresponding intensities; the present invention preferably adopts the second-order diffraction effect as the diffraction effect adopted by the optical dispersion conversion module 41; after the interference broadband light undergoes the dispersion effect of two-order diffraction, light of different wavelengths is clearly distinguished in space, and light at different spatial positions is then photoelectrically converted into electrical signals of corresponding intensities, which effectively improves the accuracy of demodulation of the external liquid environment pressure based on the change of the center wavelength position; the embedded module 42 captures the electrical signal and digitizes it to obtain a digital spectrum.

[0054] The embedded module 42 in the present invention can control the power drive module 43 to adjust the frequency of powering the optical dispersion conversion module 41, thereby realizing the measurement of different rates of the interference broadband light energy spectrum, meeting the measurement rate requirements in different medical environments.

[0055] The spectral demodulation unit 5 of the present invention is used, on the one hand, to monitor in real time the position of the intraocular pressure sensor 3 within the image captured by the area array CCD camera 61, allowing the operator to promptly adjust the irradiation position of the indicator light. It is also used to acquire a digital spectrum and locate the central wavelength corresponding to the spectral peak. Based on the correspondence between the central wavelength position and pressure, the pressure of the external liquid environment, i.e., the intraocular pressure, is obtained in real time. Based on the quality of the real-time spectrum, the operator can also be provided with feedback regarding whether the broadband light is aligned with the intraocular pressure sensor 3 and operational recommendations for multi-dimensional calibration adjustments. It is worth noting that the criteria for judging spectral quality include, but are not limited to, light intensity, free spectral range, signal-to-noise ratio, and frequency domain transformation results. Feedback and suggestions can be provided in the form of, but are not limited to, sound, text, graphics, indicator lights, vibration, and any combination of these media.

[0056] To achieve the above functions, the spectrum demodulation unit 5 of the present invention includes at least one central processing unit (CPU). The demodulation steps are executed in the CPU in the form of programs or instructions. These programs or instructions are stored in a permanent memory and can be accessed by the CPU at any time. It is worth noting that CPUs include, but are not limited to, CPUs, MCUs, MPUs, DSPs, FPGAs, and ASICs. Persistent memory includes, but is not limited to, programmable ROMs, Flash ROMs, optical disks, floppy disks, and hard disks.

[0057] The present invention realizes a detection and demodulation method of a Fabry-Pérot structure intraocular pressure sensor based on an embedded system and a non-contact optical microscopy detection system.

[0058] 3 , the spectral demodulation unit 5 of the present invention obtains intraocular pressure based on the digital spectrum, including the following steps: S1: determining the position of the optical microscope system; S2: reading the digital spectrum to obtain raw spectral data; S3: extracting the maximum value of the raw spectral data, comparing the maximum value with a preset threshold, and determining whether the maximum value is not less than the preset threshold. If so, proceed to step S4; otherwise, proceed to step S1; S4: performing spectral interpolation processing on the raw spectral data and performing FFT filtering to restore the spectral data of the interfering broadband light; S5: using a peak-finding algorithm to separate the spectral data of the interfering broadband light and obtain the central wavelength position of the spectral data of the interfering broadband light; S6: obtaining the intraocular pressure through the central wavelength position.

[0059] According to the sensing principle of the FP resonant cavity, when the reflectivity of the two reflective surfaces is less than 4%, most of the light perpendicularly incident on the FP resonant cavity will be transmitted out from the other side, and only the first and second reflected light will maintain the same energy level. Therefore, the FP resonant cavity composed of such low-reflectivity reflective surfaces can simplify multi-beam interference to dual-beam interference; therefore, the expression for the intensity of the reflected interference light is: .

[0060] Where: I FP is the intensity of the reflected interference light, I0 is the intensity of the incident light, R1 and R2 are the reflectivity of the two surfaces respectively, n is the refractive index of the medium between the two reflecting surfaces, L is the distance between the two reflecting surfaces, and λ is the wavelength of light within the spectral range of the light source.

[0061] If one of the reflective surfaces of the FP resonant cavity is a pressure-sensitive film, the film will undergo axial deformation under the action of pressure. At this time, the cavity length L of the FP resonant cavity will be shortened by ΔL. This will introduce a phase deviation ΔΦ related to the change in cavity length into the interference spectrum, which is calculated as follows: .

[0062] Where n is the refractive index of the medium between the two reflecting surfaces, λ is the wavelength of light within the spectral range of the light source, and ΔL is the change in the length of the resonant cavity; in the interference spectrum, this is manifested as a wavelength shift corresponding to the peak of the entire spectrum.

[0063] According to solid mechanics theory, the center of a square diaphragm will undergo axial deformation under static pressure. The relationship between the maximum axial deformation ΔL of the diaphragm and the static pressure P is as follows: .

[0064] Where: υ is the Poisson's ratio of the diaphragm, E is the Young's modulus of the diaphragm, t is the thickness of the diaphragm, and α is the side length of the diaphragm.

[0065] From the above formula, we can see that the change in pressure is linearly related to the maximum axial deformation of the diaphragm, ΔL. This relationship also linearly relates to the wavelength shift corresponding to the spectral peak. Therefore, the system can decode the corresponding pressure change by the wavelength shift corresponding to the spectral peak.

[0066] Specifically, after preliminarily determining the position of the optical microscope system, the spectrum demodulation unit 5 reads the digital spectrum output by the spectrum acquisition unit 4 to obtain raw spectrum data; extracts the maximum value of the raw spectrum data and compares the maximum value with a preset threshold value. If the maximum value is less than the original threshold value, the spectrum demodulation program will determine that the broadband light is not vertically incident on the intraocular pressure sensor 3. At this time, the system preferably prompts the operator to adjust the spatial position of the broadband light focus by adjusting the multi-dimensional displacement stage and combining the real-time image obtained by the microscopic imaging positioning unit 6, and re-determine the position of the optical microscope system until the maximum value of the read raw spectrum data is greater than or equal to the preset threshold value. At this time, the system will determine that the broadband light has been vertically incident on the intraocular pressure sensor 3, and then perform spectrum interpolation processing on the raw spectrum data and perform FFT filtering to restore the spectrum data of the interference broadband light; then use the peak finding algorithm to separate the spectrum data of the interference broadband light, obtain the center wavelength position of the spectrum data of the interference broadband light, obtain the center wavelength of the interference spectrum peak of the real-time FP resonant cavity, and then obtain the pressure of the external liquid environment at this time, that is, the intraocular pressure, based on the correspondence between the center wavelength and the pressure.

[0067] In the present invention, the spectrum demodulation unit 5 is used to demodulate the received digital spectrum. According to the characteristics of this system, when broadband light is incident perpendicularly on the plane reflector, the system receives the strongest specularly reflected light. Because the surface of the intraocular pressure sensor is rougher than the reflector, the intensity of the received interfering broadband light can only reach 50% of the intensity of the specularly reflected light. Therefore, the preset threshold is set at 50% of the maximum specularly reflected light intensity. In other words, the preferred preset threshold in the present invention is 50% of the specularly reflected light intensity when broadband light is incident perpendicularly on the plane reflector.

[0068] To facilitate understanding, the present invention describes the complete working process of the optical microscope system for intraocular pressure measurement as follows: the indicator light emitted by the indicator light source 62 is reflected by the lens group 21, enters the objective lens 22, and is focused onto the surface of the intraocular pressure sensor 3 and reflected. The return light is received by the area array CCD camera 61 through the objective lens 22 and the lens group 21, and the generated image is transmitted to the screen of the host computer (spectral demodulation unit 5) in real time; the multi-dimensional displacement stage is adjusted so that the intraocular pressure sensor 3 appears in the center of the field of view of the area array CCD camera 61.

[0069] At this point, broadband light emitted by broadband light source 11 enters the first port of fiber circulator 12, exits the second port of fiber circulator 12, enters fiber collimator 13, is reflected by lens assembly 21, is focused by objective lens 22, and is vertically incident on the FP resonant cavity of intraocular pressure sensor 3. After entering the cavity, the broadband light is reflected by multiple surfaces and interferes with each other. The resulting interfering broadband light is collected by objective lens 22, reflected by lens assembly 21, enters fiber collimator 13, enters the second port of fiber circulator 13, exits the third port of fiber circulator 13, and finally enters spectrum acquisition unit 4.

[0070] The interference broadband light enters the spectrum acquisition unit 4 , and the optical dispersion conversion module 41 and the embedded module 42 convert the energy spectrum of the interference broadband light into a digital spectrum and transmit it to the spectrum demodulation unit 5 .

[0071] The spectral demodulation unit 5 demodulates the received digital spectrum. The present invention uses a computer as the spectral demodulation unit 5. After the obtained raw spectral data is subjected to spectral interpolation, FFT filtering, threshold setting, peak finding algorithm, threshold peak separation, and finding the wavelength coordinates corresponding to the spectral peak, the real-time central wavelength of the interference spectrum peak of the FP resonant cavity and the corresponding pressure of the external liquid environment at that time, i.e., the intraocular pressure, are obtained, thereby enabling rapid non-contact optical detection and demodulation of the intraocular pressure.

[0072] In a specific embodiment of the present invention, the measurement process is as follows: 1) placing the intraocular pressure sensor 3 in a pressure-controllable liquid container and positioning the intraocular pressure sensor 3 using the microscopic imaging positioning unit 6; setting the single pressurization amount to 3.75 mmHg, and pressurizing from 3.75 mmHg to 37.5 mmHg, performing steps 2 to 4 after each pressurization; 2) reading the digital spectrum output by the spectrum acquisition unit 4 to obtain raw spectrum data, as shown in FIG4 ; 3) interpolating the raw spectrum data and performing FFT filtering to restore the interference spectrum data generated by the FP resonant cavity of the intraocular pressure sensor at this pressure, as shown in FIG5 ; 4) using a peak-finding algorithm to threshold the interference spectrum data, recording the coordinates of the maximum value of a single spectrum peak, that is, obtaining the central wavelength position of the spectrum peak at this pressure; 5) performing a linear fit between the position of the central wavelength of the spectrum peak at each pressure and the corresponding pressure data to obtain the sensing sensitivity of the intraocular pressure sensor 3, and then obtaining the corresponding pressure, that is, the intraocular pressure, based on the position of the central wavelength of the spectrum peak and the sensing sensitivity.

[0073] The specific linear fitting process is shown in FIG7 . The fitting result is a linear function of the center wavelength position (y) of the spectrum peak with respect to the pressure (x): y=0.03263x+752.97241. The slope of the linear function is the sensing sensitivity of the intraocular pressure sensor 3 .

[0074] FIG6 shows the interference spectrum data detected and restored by the intraocular pressure sensor 3 at different pressures.

[0075] As shown in Figure 7, this test experiment shows that the sensitivity of intraocular pressure sensor 3 is 32.63 pm / mmHg. Furthermore, this embodiment also tests the demodulation accuracy of the system. When the intraocular pressure sensor is at a fixed pressure, the pressure demodulation accuracy of the demodulation system is controlled within the range of ±1.5 mmHg.

[0076] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. An optical microscopy system for measuring intraocular pressure, characterized in that: It comprises a spatial optical sensing unit (1), a light transmission unit (2), an intraocular pressure sensor (3), a spectrum collection unit (4) and a spectrum demodulation unit (5); wherein: The spatial optical sensing unit (1) is connected to the spectrum collection unit (4); The spectrum acquisition unit (4) is connected to the spectrum demodulation unit (5) via a transmission link 1 (7); The intraocular pressure sensor (3) is provided with a Fabry-Perot microcavity; The broadband light emitted by the spatial optical sensing unit (1) is vertically incident on the Fabry-Perot microcavity through the light transmission unit (2), thereby obtaining interference broadband light; The interference broadband light passes through the light transmission unit (2) and the spatial optical sensing unit (1) and is then transmitted to the spectrum collection unit (4); The spectrum acquisition unit (4) converts the interference broadband light into a digital spectrum and transmits the digital spectrum to the spectrum demodulation unit (5); The spectrum demodulation unit (5) acquires intraocular pressure according to the digital spectrum.

2. The optical microscope system for intraocular pressure measurement according to claim 1, characterized in that: The spatial optical sensing unit (1) comprises a broadband light source (11), an optical fiber circulator (12), and an optical fiber collimator (13); wherein the broadband light source (11) and the optical fiber circulator (12), the optical fiber circulator (12) and the optical fiber collimator (13), and the optical fiber circulator (12) and the spectrum collection device (4) are all connected via optical fibers; the broadband light source (11) is used to emit the broadband light; the broadband light is sequentially input into the light transmission unit (2) through the optical fiber circulator (12) and the optical fiber collimator (13); and the interference broadband light is sequentially transmitted through the light transmission unit (2), the optical fiber collimator (13), and the optical fiber circulator (12) before being transmitted to the spectrum collection unit (4).

3. The optical microscope system for intraocular pressure measurement according to claim 1, characterized in that: The wavelength range of the broadband light is 750nm-950nm.

4. The optical microscopy system for intraocular pressure measurement according to any one of claims 1 to 3, characterized in that: It also includes a microscopic imaging positioning unit (6); the microscopic imaging positioning unit (6) is connected to the spectral demodulation unit (5) via a second transmission link (8); the indication light emitted by the microscopic imaging positioning unit (6) is incident on the Fabry-Perot microcavity via the light transmission unit (2) to obtain reflected indication light; the reflected indication light is received by the microscopic imaging positioning unit (6) for imaging after passing through the light transmission unit (2) to obtain a real-time image, and the real-time image is transmitted to the spectral demodulation unit (5).

5. The optical microscope system for intraocular pressure measurement according to claim 4, characterized in that: The microscopic imaging positioning unit (6) comprises a CCD camera (61) and an indication light source (62); the indication light source (62) is used to emit the indication light; the CCD camera (61) is signal-connected to the spectrum demodulation unit (5).

6. The optical microscope system for intraocular pressure measurement according to claim 4, characterized in that: The light transmission unit (2) comprises a lens group (21) and an objective lens (22) which are arranged in sequence along the light path.

7. The optical microscope system for intraocular pressure measurement according to claim 4, characterized in that: The spectrum acquisition unit (4) comprises an optical dispersion conversion module (41), an embedded module (42) and a power drive module (43); wherein the power drive module (43) supplies power to the optical dispersion conversion module (41) under the control of the embedded module (42); the optical dispersion conversion module (41) converts the interference broadband light of different wavelengths into an electrical signal through a diffraction effect, and transmits the electrical signal to the embedded module (42); and the embedded module (42) is used to digitize the electrical signal to obtain the digital spectrum.

8. The optical microscope system for intraocular pressure measurement according to claim 4, characterized in that: The spectrum demodulation unit (5) comprises at least one central processor.

9. The optical microscope system for intraocular pressure measurement according to claim 8, characterized in that: The spectrum demodulation unit (5) acquires intraocular pressure according to the digital spectrum, comprising the following steps: S1: Determine the position of the optical microscope system; S2: reading the digital spectrum to obtain original spectrum data; S3: extracting the maximum value of the original spectrum data, comparing the maximum value with a preset threshold, and determining whether the maximum value is not less than the preset threshold. If so, proceed to step S4, otherwise proceed to step S1; S4: performing spectrum interpolation processing on the original spectrum data and performing FFT filtering to restore the spectrum data of the interference broadband light; S5: using a peak-finding algorithm to separate the spectral data of the interference broadband light into peaks, and obtaining the central wavelength position of the spectral data of the interference broadband light; S6: Obtaining intraocular pressure through the central wavelength position.

10. The optical microscope system for intraocular pressure measurement according to claim 9, characterized in that: The preset threshold is 50% of the mirror reflected light intensity when the broadband light is vertically incident on the plane reflector.

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