KR102371523B1 - Intraocular pressure measuring device - Google Patents

Abstract

The present invention particularly relates to an intraocular pressure measuring device using a Mykeno light-emitting material that emits light due to mechanical deformation. It is composed of a measuring sensor that detects the degree of deformation generated in the deformable film due to the unit, wherein the deformable film is a composite material in which a photomechanical light emitting material having a property of emitting light when mechanical deformation is applied and a flexible resin material are mixed with each other, By adopting a Mykeno light-emitting film that is manufactured in the form of a thin film that can be attached to the eye and emits light in response to mechanical changes on the surface, the accuracy can be significantly improved compared to the conventional Goldman tonometer or Pascal tonometer, but even for beginners who are not experts It is intended to provide a device for measuring intraocular pressure that can be measured so that anyone can easily prevent eye diseases that can happen unexpectedly at home, so that a dramatic improvement in eye health management can be achieved.

Description

Intraocular pressure measuring device

The present invention relates to an intraocular pressure measuring device, and more particularly, to an intraocular pressure measuring device using a micheno light-emitting material that emits light due to mechanical deformation.

Sight is the sense that people depend on most in their life. If you lose your sight, your daily life can come to a complete halt in an instant. Glaucoma is a disease that gradually causes loss of vital vision. Glaucoma is the most common disease among the three leading causes of blindness.

In particular, normal-tension glaucoma is a disease in which the anterior chamber angle is open while the normal range (21 mmHg or less) is present, and characteristic glaucoma optic nerve damage and visual field defects appear accordingly. It is characterized by low intraocular pressure and almost no subjective symptoms. Because the change in the field of vision also progresses slowly, in most cases the patient does not even notice the disease until the end of glaucoma. Peripheral vision decreases as the disease progresses, and at the end of the day, it appears as if you are looking at an object through a tunnel.

Normal tension glaucoma has few subjective symptoms, making early diagnosis difficult. Therefore, rather than visiting a hospital for suspicion of glaucoma, it is often discovered by chance while having other ophthalmic symptoms or visiting an ophthalmologist for a health check-up.

Visual field examination is essential to evaluate the function of the optic nerve. This is because glaucoma progresses from peripheral vision impairment to blindness. Visual field examination is very important not only for diagnosing glaucoma, but also for monitoring disease progression and progress.

In addition, as the glaucoma progresses, the optic nerve papilla test is necessary because the optic nerve disc shows glaucoma damage. The retinal nerve fiber layer test to measure the thinning of the retinal nerve fiber layer as glaucoma progresses is a useful test for diagnosis.

However, the most important factor in glaucoma is intraocular pressure (IOP). Normal-tension glaucoma patients have intraocular pressure in the normal range, but measurement of intraocular pressure is very important because it is also a risk factor for the progression of glaucoma.

Monitoring of intraocular pressure through a tonometer is essential to prevent the risk of glaucoma. As can be seen in Figure 1a, the human eye, the visual system composed of the cornea (C), sclera (D), iris (B), lens (A), and ciliary band fibers, is a sensory organ that receives and transmits visual information to the brain. . The eye has two body cavities, the posterior chamber surrounded by the sclera (D) and lens, and the anterior chamber surrounded by the cornea (C), iris (B) and lens. These two rooms are filled with aqueous body fluids. Glaucoma is caused by damage to the optic nerve by loss of retinal ganglion cells (RGCs).

Elevated intraocular pressure is the most important symptom among various risk factors related to eye health. It is mainly associated with increased water pressure due to increased aqueous humor in the eye. In a normal person, aqueous fluids are released through the trabeculae to maintain adequate intraocular pressure. However, in patients with glaucoma, some problems can cause the trabecular meshwork to malfunction, aqueous fluids are no longer drained, and intraocular pressure increases, damaging the optic nerve, leading to glaucoma. As can be seen in FIG. 1B , normal intraocular pressure is 10 to 21 mmHg (average 15 mmHg), the difference in intraocular pressure between the right and left eyes is less than 3 mmHg, and the intraocular pressure in glaucoma patients is 21 mmHg or more. Statistically, a value of 21 mmHg is widely considered to distinguish between normal and abnormal intraocular pressure. Typically, glaucoma can be prevented by detecting and treating abnormal pressure increases through regular intraocular pressure monitoring. Therefore, early diagnosis of glaucoma is important.

Among conventional measuring devices related to intraocular pressure measurement, the Goldman tonometer is widely used as a standard diagnostic method. Goldman tonometer is a measuring instrument based on Applanation Tonometry to which Imbert-Fick's law is applied, which states that internal pressure is equal to external force divided by the area of the applanation plane. The key principle of Imbert-Fick's law is that the force required to flatten or protrude the local surface of a sphere is equal to the product of the pressure inside the sphere and the area applied. At this time, when a certain local area is flattened, the eye pressure is determined from the force applied to cancel the stiffness of the cornea (C) and the force applying the deformation to the cornea (C).

The Goldman tonometer can measure relatively accurate intraocular pressure, but it may not be accurate when the surface of the cornea (C) is not normal, and may be affected by the thickness of the cornea (C) or the concentration of fluorescent dye. Among them, when the thickness of the cornea (C) is thin, it is measured lower than the actual intraocular pressure, and when the collagen of the cornea (C) is increased and thickened, it is measured high. However, when the secondary thickness increases due to corneal (C) edema, the result is measured lower than the actual intraocular pressure.

Goldman tonometers are contact tonometers, whereas air puff tonometers are non-contact tonometers. However, the Goldman tonometer has higher accuracy than other tonometers, but has the disadvantage that it requires an ophthalmologist's measurement because it requires anesthesia and the difficulty of measurement is high.

The Pascal tonometer (dynamic contour tonometry, PAS CALㄾ) is a tonometer designed to be mounted on a slit lamp microscope and not to cause deformation of the cornea (C) without flattening the cornea (C) and not to be affected by the characteristics of the cornea (C). is made as close to the curvature of the cornea (C) as possible and contacts the cornea (C) to directly measure the intraocular pressure. When this tonometer is in contact with the apex of the cornea (C), there is little change in the shape of the surface of the cornea (C). It is directed equally towards the sensor.

However, the Pascal tonometer is difficult to measure the intraocular pressure compared to previously designed tonometers. For accurate measurement of intraocular pressure, the sensor tip must be in contact with the patient's cornea (C) for at least 4 to 5 seconds compared to Goldman applanation tonometer. cannot be measured.

Although the air puff tonometer has been considered a quick and simple method for measuring intraocular pressure in children and other groups of non-compliant patients, it is not considered an accurate method of measuring intraocular pressure. Therefore, there is an urgent need for new alternatives that are more accurate, reliable and tractable.

Laid-Open Patent Publication No. 10-2019-0074637 (published date: 2019.06.28.)

Accordingly, the present invention provides a device for measuring intraocular pressure that can significantly improve accuracy compared to the conventional Goldman tonometer or Pascal tonometer, and can measure even a novice, not an expert, so that anyone can easily prevent eye diseases that may occur unexpectedly at home. would like to provide

To achieve this object, an intraocular pressure measuring device according to the present invention includes a deformable film made of a flexible material, a deformation generating unit that applies a force to the deformable film to cause deformation in the deformable film, and a deformation generating unit generated in the deformable film by the deformable film. It is composed of a measuring sensor that detects the degree of deformation, and the deformation film is a composite material in which a photomechanical light-emitting material having a property of emitting light when a mechanical stimulus is applied and a flexible resin material are mixed with each other in the form of a thin film that can be attached to the eye It is characterized in that it is a micheno light-emitting film 10 that is manufactured and emits light in response to a mechanical change of the surface.

Here, the micheno light-emitting film 10 is preferably formed in a curved surface having the same curvature as the outer surface of the eyeball.

Also, the strain generating unit is preferably a micro air blower 24 that blows air onto the surface of the micro-light-emitting film 10 to apply micro-strain to the surface of the micro-light-emitting film 10 .

The measuring sensor for detecting the degree of deformation is preferably a photometric sensor 23 for measuring the intensity of visible light by receiving and amplifying the microscopic visible light generated due to the microscopic deformation of the surface of the microscopic light emitting film 10 .

Preferably, the Mykeno light emitting film 10, the deformation generating unit, and the photometric sensor 23 are installed on the frame 30 manufactured to be mounted on the curve of the face.

At this time, the Mykeno light emitting film is preferably placed on the loading jig 21 installed in the frame 30 so that it can be gripped while maintaining the spherical shape and contacted with the eye by moving forward or backward in a sliding manner. (10) is installed.

In this case, the loading jig 21 is preferably connected to the periphery of the Mykeno light emitting film 10 or both sides of the Mykeno light emitting film 10 and has an elastic support member 22 having a greater elastic force than that of the Mykeno light emitting film 10 . ) to hold the micheno light emitting film 10 .

The device for measuring intraocular pressure according to the present invention can significantly increase the accuracy compared to the conventional Goldman tonometer or Pascal tonometer, and even a beginner, not an expert, can measure it, so that anyone can easily prevent eye diseases that may occur unexpectedly at home. There is an effect that a dramatic improvement in eye health care can be achieved.

1A is a cross-sectional view showing each configuration of an eyeball;
1b is a graph comparing normal intraocular pressure and glaucoma intraocular pressure;
Figure 2a is a cutaway perspective view of a spherical shell modeling the cornea (C) and sclera (D);
2B is a cutaway perspective view of a viscous pressurized fluid modeling a vitreous body fluid;
2c is a graph showing that a pressure of 330 kPa is applied for 40 ms;
Fig. 2d is a cross-sectional view showing that the spherical shell of Fig. 2a is deformed at various pressures;
Figure 2e is a graph showing the strain of the spherical shell at different pressures of Figure 2a;
3 is a graph showing the material and tissue photograph and wavelength-luminosity and XRD pattern of the micheno light-emitting film;
4 is a conceptual diagram showing the basic configuration of an intraocular pressure measuring device according to the present invention;
5 is a graph showing that two peaks are observed at each pressure;
6 is a graph showing the relationship between the optical signature and pressure;
7 is a perspective view showing an intraocular pressure measuring device according to an embodiment;
Fig. 8 is a plan view of Fig. 7;
9 is a partial plan view showing the process in which the Mykeno light emitting film is seated on the surface of the eyeball;
10 is a table showing the behavioral characteristics of the spherical shell and viscous fluid model;

Specific structural or functional descriptions presented in the embodiments of the present invention are only exemplified for the purpose of describing embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention may be implemented in various forms. In addition, it should not be construed as being limited to the embodiments described herein, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, 1. The configuration of the intraocular pressure measuring device according to the present invention will be briefly described, in turn 2. The micheno light emitting film 10 used in the invention and the micheno light emitting film used in the actual experiment for the test of the present invention The manufacturing process of (10), the modeling method for the experiment, and the experimental results will be described, and then 3. Specific additional embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 4, the apparatus for measuring intraocular pressure according to the present invention includes a deformable film made of a flexible material, a deformation generating unit that applies a force to the deformable film to cause deformation in the deformable film, and a deformation generating unit generated in the deformable film It consists of a measuring sensor that detects the degree of deformation.

Here, the deformable film is a composite material in which a photomechanical light-emitting material and a flexible resin material are mixed with each other to emit light when mechanical deformation occurs. This is the induced micheno light-emitting film (10).

The photomechanical light emitting material is a material in which light is generated in response to mechanical stimuli such as friction, force, pressure and torque, SrAl2O4: Eu, Dy (SAO), ZnS: Cu and ZnS: Various organic or inorganic materials such as Mn It may be one of the fine particles. This luminescence phenomenon will be referred to as 'mycheno luminescence' (ML) hereinafter. Here, the mychenoluminescence phenomenon is also called fracto-, piezo- or elasticoluminescence.

For reference, the micenoluminescence (ML) material adopted in the experiment described in this description is ZnS:Cu (LONCO Company Limited) ML powder among the materials, and the flexible resin material is polydimethylsiloxane (PDMS).

<Modeling analysis of the correlation between the internal pressure of the eyeball and the behavior of the cornea (C)>

In order to measure intraocular pressure using the mychenoluminescence (ML) phenomenon, fluid-structure interaction analysis (FSI) analysis is required to analyze the correlation between the internal pressure of the eye and the behavior of the cornea (C). . For this purpose, 3D modeling of the spherical shell (G1) filled with fluid (mineral oil) was performed in the experimental process for the present invention, and FSI analysis was performed through ABAQUS, a commercial finite element method (FEM) analysis tool. Internal pressure and corneal (C) strain were analyzed by applying impulse pressure to the cornea (C). An experiment with a spherical shell (G1) pressurized with a fluid (mineral oil) shows the internal pressure measurement method proposed in this study.

In a simplified finite element (FE) model of the human eye for a preliminary study of internal pressure monitoring, a spherical shell (G1) corresponding to the cornea (C) and sclera (D) was first established as shown in Fig. 2a. Here, in order to increase the efficiency of the analysis and to confirm the operation of the inner components of the eye, in this spherical shell (G1) model, the ocular structure was assumed to be axially symmetric and the spherical shell (G1) was assumed to have a constant thickness and constant curvature. It was assumed that the spherical shell G1 was filled with a viscous pressurized fluid H1 representing the free body fluid shown in FIG. 2B .

At this time, for the viscoelastic analysis of the viscous pressurized fluid H1 shown in FIG. 2B, the Prony series expressed by the following equation was used.

In the above equation, the Poisson's ratio υ(t) is assumed to be a constant, τ is the relaxation time, G ₀ is the initial shear modulus, and G _∞ is the infinite shear modulus.

The spherical shell (G1) model and the viscous pressurized fluid (H1) model were designed with Lagrangian components. The interaction between two solid elements was defined using inter-surface bond constraints. The outer diameter and thickness of the spherical shell G1 were arbitrarily set to 65 mm and 2 mm, respectively. The physical properties based on the isotropy of each element are summarized in Table 1 interposed in FIG. 10 . The commercial finite element code, ABAQUS, was used for all calculations in this study. Mode-based steady-state dynamic analysis was used to calculate the steady-state dynamic linearized response of the system to harmonic excitation (i.e., steady-state amplitude and phase in complex form).

For the simulation of the non-contact tonometric test, the air puff corresponding to the strain generating unit prepared to cause the strain in the Mykeno luminescent film 10 was determined to be a measured collimated air pulse with a maximum pressure of 330 kPa and a duration of 40 ms. It was assumed A circle with a diameter of 3 mm is marked on the cornea C as shown in FIG. 2C .

2d shows a cross-section of the spherical shell G1 when the strain of the tip portion of the spherical shell G1 is maximum at various pressures. 2d (a) and (b) show the cross section of the spherical shell (G1) at the lowest pressure of 7 kPa, (c) and (d) show the cross section of the spherical shell (G1) at the highest pressure of 27 kPa show 2d (a) and (c) are cross-sections of the spherical shell (G1) when the spherical shell (G1) is deformed by applying time pressure, (b) and (d) are when the spherical shell (G1) is restored A cross-section of the spherical shell G1.

Here, when strain occurs at each pressure value, the maximum value of strain in all cases appears twice for various internal pressures. These two peaks are expressed in the graph of FIG. 5 , and in the symbol indicated in the form of I in the graph of FIG. 6 , the two peaks in which the upper and lower values of I appear at any one pressure value are expressed. These two peaks mean the strain when the spherical shell (G1) is deformed by the incident time pressure and when it is restored by the elasticity of the spherical shell (G1).

Here, the strain of the Mykeno light emitting film 10 is measured using a photometric sensor 23 . Here, the photometric sensor 23 is a representative photomultiplier tube (PMT) sensor. However, any sensor that can measure the intensity of visible light can be adopted.

Tonometry evaluation is performed by the aforementioned fluid-structure interaction analysis (FSI) analysis.

The pressurized spherical shell G1 at 7.5, 10, 12.5, 15 and 17.5 kPa is excited by the vibrator. The experimental results are shown graphically in FIG. 5 . Here, the maximum strain appears twice and the release peak is observed twice at each pressure. These are the light emitted during the deformation process and the light emitted during the recovery process. An optical signature is proposed in this study to find the relationship between the characteristics of the emitted light and the internal pressure. It is the ratio of the area expressed as the product of the intensity and duration of the ML. This optical signature can be expressed by the following equation.

Subscripts 1 and 2 of the area represent the first luminescence (eg, transformation process) and second luminescence (eg, recovery process) of the ML, respectively.

There is a linear relationship between the internal pressure and the optical signature. A linear relationship is established between the internal pressure and the optical signature as shown in the graphs of FIGS. 6A and 6B . Subscripts 1 and 2 of intensity and area in the above formula represent the first luminescence (eg, transformation process) and the second luminescence (eg, recovery process) of the mychenoluminescence, respectively.

In FIG. 6 , a blue symbol I indicates a range of a maximum value and a minimum value. Each pressure and red solid line is a regression line for each optical signature.

<An embodiment of the intraocular pressure measuring device according to the present invention>

Hereinafter, an embodiment of the intraocular pressure measuring apparatus according to the present invention will be described with reference to FIGS. 4 and 7 to 9 .

As briefly described above, the apparatus for measuring intraocular pressure according to the present invention is composed of a deformation film, a deformation generating unit, and a measurement sensor as shown in FIG. Correspondingly, the measuring sensor is a photometric sensor 23 that precisely measures the intensity of visible light by receiving and amplifying the fine visible light emitted when the micheno light emitting film 10 is deformed. In this case, as the photometric sensor 23 , a photomultiplier tube (PMT) sensor is representative, but other conventional sensors capable of measuring photometric intensity may also be employed.

In addition, as shown in FIG. 4 , the deformation generating unit for generating deformation in the micheno light emitting film 10 includes a micro air blower 24 that blows air on the surface of the micheno light emitting film 10 to generate pressure in a non-contact manner. is installed At this time, the air compressor 242 may be installed in the micro air blower 24 . However, any conventional unit can be adopted as long as it is a unit capable of causing minute deformation.

For reference, in the viscous fluid model H2 inside the corneal model G2 shown in FIG. 4, an injection pump S may be used as shown in FIG. .

The photometric sensor 23 shown in FIG. 4 may be measured by holding it by hand, or may be configured to be mounted on the face. To this end, in the present embodiment, a frame 30 manufactured to be mounted on the curves of the face is provided.

Specifically, as shown in FIG. 7 , the frame 30 may be mounted using the ears and nose like ordinary glasses. Since the measurement does not need to be performed in both eyes at the same time, the photometric sensor 23 is installed only in one eye, but the photometric sensor 23 installed in one eye can be pulled out and replaced with the other eye.

The Mykeno light-emitting film 10 may be brought into contact with the eye by human hand, but since it may be difficult to attach by hand, in this embodiment, any additional physical contact other than the Mykeno light-emitting film 10 is not applied to the eye. As shown in Fig. 8, the Mykeno light emitting film 10 is gripped while maintaining the spherical shape, and the Mykeno is mounted on the loading jig 21 installed in the frame 30 so that it can contact the eye by moving forward or backward in a sliding manner. A light emitting film 10 is installed. At this time, the curvature constituting the spherical shape of the micheno light emitting film 10 coincides with the curvature of the eyeball.

In addition, the loading jig 21 is connected to the periphery of the Mykeno light-emitting film 10 or both sides of the Mykeno light-emitting film 10 and is an elastic support member 22 having a greater elastic force than that of the Mykeno light-emitting film 10 . The light emitting film 10 is gripped.

That is, in the loading jig 21, the flexible elastic support member 22 is shown in Figs. Hold the Mykeno light emitting film 10 as shown. Therefore, the installation of the micheno light emitting film 10 can be made without hindrance due to the solid object coming into contact with the eye while the micheno light emitting film 10 is in contact with the eyeball.

A process in which the Mykeno light emitting film 10 is gently seated on the eyeball due to the elastic support member 22 is illustrated in FIG. 9 . At this time, as shown in FIG. 8 , a jig sliding wheel 261 for varying the loading jig 21 in a sliding manner may be installed in the measurement module 20 so as to slowly approach the loading jig 21 in the eye direction. there is.

In addition, since each person has a different facial skeleton, the distance between the photometric sensor 23 and the eye may be different, which may cause an error. To prevent this, the photometric sensor 23 can adjust the distance between the photometric sensor 23 and the eye. ), a sensor sliding wheel 262 that varies may be installed. Here, a distance measuring sensor (not shown) may be additionally installed to generate a signal when the distance between the photometric sensor 23 and the ocular surface falls within a standard range.

The control unit 25 has a built-in power supply and a communication unit, and a circuit for receiving signals from each sensor is built-in, so that measured luminous intensity data can be exchanged between a smart phone or a server.

On the other hand, the gaze fixation induction module 40 may be installed in the frame 30 in the remaining eye area other than the eye on the side where the measurement module 20 is installed. In particular, the gaze fixation induction module 40 prevents the Mykeno light emitting film 10 from being seated in the correct position due to the complex movement of the eyeball due to the protective action of the eyes during the installation process of the Mykeno light emitting film 10 . For this purpose, it acts to generate a visual signal for gaze concentration that can fix the gaze.

In addition, the measurement module 20 and the eyepiece sealing member 31 that seals the skin around the eyes is installed to block the surrounding light, so that the photometric measurement can be made more precisely.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes can be made within the scope without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

A: Lens B: Iris
C: cornea D: sclera
E: optic nerve F: vitreous humor
G1: spherical shell G2: corneal model
H1 : Viscous pressurized fluid H2 : Viscous fluid model
L : Emitted visible light P : Force applied for deformation
S: injection pump 10: micheno luminescent film
20: measuring module 21: loading jig
22: elastic support member 23: photometric sensor
24: micro air blower 25: control unit
30: frame 31: eyepiece sealing member
40: gaze fixed induction module 242: air compressor
261: jig sliding wheel 262: sensor sliding wheel
263: power switch 264: measurement start switch

Claims (7)

a deformable film made of a flexible material;
a deformation generating unit for applying a force to the deformable film so that the deformable film is deformed;
It is composed of a measuring sensor for detecting the degree of deformation generated in the deformation film due to the deformation generating unit,
The deformable film is a composite material in which a photomechanical light-emitting material and a flexible resin material, which emit light when mechanical deformation is applied, are mixed with each other. is an induced micheno light-emitting film (10),
The mykeno light-emitting film 10 is formed in a curved surface having the same curvature as the outer surface of the eyeball,
The strain generating unit is a micro air blower 24 that blows air onto the surface of the micro light emitting film 10 to apply micro strain to the surface of the micro light emitting film 10,
The measurement sensor for detecting the degree of deformation is a photometric sensor 23 for measuring the intensity of visible light by receiving and amplifying the microscopic visible light generated due to the microscopic deformation of the surface of the microscopic light emitting film 10, characterized in that Tonometry device. delete delete delete According to claim 1,
The Mykeno light emitting film (10), the deformation generating unit, and the photometric sensor (23) are installed in a frame (30) manufactured to be mounted on the curve of the face. 6. The method of claim 5,
The Mykeno light-emitting film 10 is mounted on a loading jig 21 installed in the frame 30 so that it can be gripped while maintaining the spherical shape and brought into contact with the eye by moving forward or backward in a sliding manner. An intraocular pressure measuring device, characterized in that it is installed. 7. The method of claim 6,
The loading jig 21 is connected to the periphery of the Mykeno light-emitting film 10 or both sides of the Mykeno light-emitting film 10 and is an elastic support member 22 having greater elasticity than the Mykeno light-emitting film 10 . An intraocular pressure measuring device, characterized in that it holds the light emitting film (10).

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