KR20220006730A - Portable IOP(IntraOcular Pressure) measurement based on cornea structural changes and its instrumentation - Google Patents

Abstract

An object of the present invention is to provide a portable intraocular pressure measurement device based on a structural variation of a cornea. That is, in the present invention, a change in intraocular pressure is sensed by accurately measuring a change in the curvature and thickness of the cornea in an optical manner. In this way, it is possible to measure the change in intraocular pressure in a non-contact, self-measurement and very economical way. Provided is the portable intraocular pressure measurement device based on corneal structural variation, wherein in this respect, another object of the present invention is to enable glaucoma patients to routinely detect changes in their intraocular pressure and ultimately to prevent the progression of glaucoma disease, thereby reducing related personal-social costs.

Description

{Portable IntraOcular Pressure (IOP) measurement based on cornea structural changes and its instrumentation}

The present invention relates to a portable intraocular pressure measuring device, and more particularly, to a portable intraocular pressure measuring device for measuring intraocular pressure in a simple manner based on a structural variation of the cornea using a portable device.

IntraOcular Pressure (IOP) is defined as the pressure applied to the fluid in the eyeball. Glaucoma is recognized as a disease in which the optic nerve is gradually damaged and visual field defects progress and eventually leads to blindness. Glaucoma is the second leading cause of blindness worldwide, and once onset is impossible to cure and is a chronic disease that requires continuous management and treatment due to the nature of the disease. In Korea, with the advent of an aging society and the development of diagnostic technology, the prevalence of glaucoma is continuously increasing rapidly. According to the National Health Insurance Corporation sample cohort database, the prevalence of glaucoma increased from 1.6% to 3.4% over the past 11 years, and it was confirmed that the incidence, not the prevalence, also increased from 1.2% to 1.8% during the same period. In addition, according to a recent study result, according to a 2013 research report by the National Health Insurance Corporation’s Health Insurance Policy Research Institute, the social costs of hypertension and diabetes were KRW 3.86 trillion and KRW 3.1 trillion, respectively, and the social cost of glaucoma was KRW 2.99 trillion. (Y. Ahn and D. Jee, "Socioeconomic Costs of Glaucoma in Korea", J Korean Ophthalmol Soc (2018) 59 665-671, Non-Patent Document 1). This means that glaucoma is a disease that has a very high social cost as well as well-known chronic diseases such as hypertension and diabetes, and should be highly economically and nationally important. However, it is difficult to see that the technology capable of measuring blood pressure or glucose has been universalized for routine examination of intraocular pressure in glaucoma patients.

Currently, conventional devices for measuring intraocular pressure include contact or non-contact applanation tonometers. In the applanation tonometer, by applying a force to the center of the cornea using a solid rod or air blow, the force required to flatten a specific area is measured to convert and estimate the intraocular pressure. Alternatively, an indentation method in which a specific type of probe is pressed into the cornea to measure pressure has been proposed and is currently being used in clinical practice. In the developed countries of the related tonometer technology worldwide, technology development is being made to continuously maintain the existing technological superiority with respect to the tonometer and to make it more sophisticated, but there is no epoch-making technological progress. Meanwhile, in the domestic ophthalmic medical device market, Switzerland's Haag-Streit's Goldmann tonometer and Japan's Topcon and Nidek's pneumatic tonometers are currently leading the market, and domestic companies include Huvitz. Most of the pneumatic tonometers for ophthalmic non-contact applanation tonometers used in health checkups are made by Japanese Topcon, and the performance of Huvitz's HNT series products, a domestic manufacturer, is not technically different compared to foreign ones. It is rarely used. On the other hand, the Goldmann tonometer, a contact applanation tonometer that is considered the golden standard in clinical practice, is mostly used in clinical trials by Swiss Hagg-Streit. This reflects well the current state of the medical world, which is very conservative in determining the use of medical devices. It is necessary to secure the distinction of

On the other hand, the technological capability to continuously monitor the intraocular pressure by inserting it directly into the eyeball and a portable or wearable tonometry device is constantly being strengthened. As an example, a lens-type intraocular pressure sensor using a microfluidic channel and a lens-type intraocular pressure sensor using resistance changes due to structural deformation of the cornea have been developed. Based on technology such as "pressure measurement", 2015.11.24., Patent Document 1), Korean Patent Registration No. 1914618 ("Intraocular pressure measurement or monitoring system including an inertial sensor", 2018.10.29., A lens-type intraocular pressure measuring device (Sensimed) using the same resistance change as in Patent Document 2) was approved by the Ministry of Food and Drug Safety in 2018 and is now commercialized. However, the device according to Patent Document 2 did not achieve great results at a price that was not suitable for the market. Specifically, the cost for one use for 24 hours was announced as about US$ 526 ~ US$ 682 in the UK as of 2016 The fixed cost of software and recorder is about US$ 7,310, so it is economically difficult to access by the general public (Grace EDunbar, Bailey Yuguan Shen, and Ahmad A Aref, "The Sensimed Triggerfish contact lens). sensor: efficacy, safety, and patient perspectives" Clinical Ophthalmology 2017:11 875??882, Non-Patent Document 2). In addition, the device according to Patent Document 1 is safe and provides high repeatability, but despite the relatively high cost, it does not provide the absolute value of intraocular pressure. There are still questions about the results.

Alternatively, research and development to implant a small closed system in the eye by combining a MEMS device for intraocular pressure control and an intraocular pressure sensor is also being actively conducted. As an example, a tonometer that measures the surface strain variation of the cornea that is directly attached to the cornea in the form of a contact lens using the MEMS method and converts it into a conversion of intraocular pressure has been developed and released. This technology is well disclosed in Korean Patent Registration No. 2075143 ("Smart contact lens for intraocular pressure monitoring and manufacturing method thereof", 2020.02.03., Patent Document 3). However, in the case of such a contact lens-type tonometer, it is difficult to be widely used in the market due to the high price and inconvenience of use. In addition, the contact lens-type ocular-mounted tonometer is based on an increase in strain at the end of the cornea, and the contact lens-type tonometer is flexible or stretchable to improve wearing comfort. In the case of being made of one material, the strain change caused by the shape of the eyeball cannot be directly transmitted to the sensor, so there is a risk that the sensitivity and accuracy of intraocular pressure measurement may be deteriorated.

Another method presented as a portable tonometer is to miniaturize the existing pneumatic applanation tonometer to make it portable. A portable contact method is well disclosed in U.S. Patent No. 5,174,292 (“Hand held intraocular pressure recording system”, 1992.12.29., Patent Document 4), and a portable non-contact method is disclosed in Korean Patent Registration No. 1781429 (“Intraocular pressure recording system”). ", 2017.09.19., Patent Document 5) is well disclosed. Patent Document 4 is a domestic technology, and at the end of 2019, CNV Tech released a non-contact portable pneumatic applanation tonometer. Although a hand-held type of press-fit or pneumatic tonometer has been developed and used, its use is also limited and contains many questions about accuracy.

1. US Patent Registration No. 9,192,298 ("Contact lens for intraocular pressure measurement", 2015.11.24.) 2. Korean Patent Registration No. 1914618 (“Intraocular pressure measurement or monitoring system including inertial sensor”, 2018.10.29.) 3. Korean Patent Registration No. 2075143 ("Smart contact lens for intraocular pressure monitoring and manufacturing method thereof", 2020.02.03.) 4. US Patent No. 5,174,292 (“Hand held intraocular pressure recording system”, 1992.12.29.) 5. Korean Patent Registration No. 1781429 ("Intraocular pressure measuring device", 2017.09.19.) 6. Korean Patent Registration No. 1646222 (“Polymer-based artificial eye manufacturing method and device”, 2016.08.01.)

1. Y. Ahn and D. Jee, “Socioeconomic Costs of Glaucoma in Korea”, J Korean Ophthalmol Soc (2018) 59 665-671. 2. Grace EDunbar, Bailey Yuguan Shen, and Ahmad A Aref, “The Sensed Triggerfish contact lens sensor: efficacy, safety, and patient perspectives” Clinical Ophthalmology 2017:11 875??882. 3. J. Hjortdal and P. K. Jensen, “In vitro measurement of corenal strain, thickness, and curvature using digital image processing” Acta Ophthalmol. Scand. 1995, 73: 5-11. 4. N. Ethlers, T. Bramsen and S. Sperling, “Applanation tonomertry and cenetral corneal thickness”, Acta Ophthamologica, 1975, 53, 34-43.

Similar to the development trend of customized medical devices classified as precision medicine, the development direction of measurement technology related to physical quantities of the human body, such as intraocular pressure, which is recognized as a measure of the etiology and treatment of glaucoma disease, is mainly focused on the development of wearable or portable tonometer. In particular, technology development for portable tonometers, which are essential for regulating intraocular pressure in glaucoma patients, such as a portable blood glucose meter for blood sugar control in diabetic patients and a portable blood pressure monitor in hypertensive patients, is being actively developed.

The present invention relates to the development of a relatively simple and economical portable tonometer by devising a non-contact and portable tonometry method of a new concept, thereby supplementing the disadvantages of the existing intraocular pressure technology. Specifically, it is an object of the present invention to provide a portable intraocular pressure measurement device based on a structural variation of the cornea. That is, in the present invention, changes in intraocular pressure are detected by precisely measuring changes in the curvature and thickness of the cornea in an optical manner. In this way, it is possible to measure the change in intraocular pressure in a non-contact, self-measurement and very economical way. In this respect, another object of the present invention is to enable a glaucoma patient to routinely detect changes in their intraocular pressure and ultimately prevent the progression of glaucoma disease, thereby reducing the associated personal-social cost. To provide a portable intraocular pressure measurement device based on

The portable intraocular pressure measuring apparatus 100 based on the structural variation of the cornea of the present invention for achieving the above object is spaced apart from each other at a predetermined distance and angle, and a plurality of images obtained by taking images of the cornea at the same time dog image acquisition unit 110; A curvature calculator 121 that calculates the curvature of the cornea using a plurality of images simultaneously acquired by each of the image acquisition unit 110, the curvature of the cornea calculated by the curvature calculator 121 and a predetermined correction factor The intraocular pressure calculator 122 that calculates the intraocular pressure using an operation unit 120 including an information storage unit 123 for storing; may include

At this time, the curvature calculating unit 121 calculates the curvature by using a shape difference generated between images of a plurality of corneas taken simultaneously as the image acquisition units 110 are spaced apart from each other at a predetermined distance and angle. can In addition, the curvature calculating unit 121 may obtain a shape of the tip of the cornea from the image of the cornea acquired by the image acquisition unit 110 , and calculate the curvature by using a plurality of shapes of the tip of the cornea.

In addition, the intraocular pressure measuring apparatus 100, the operation unit 120, using at least one image acquired by the at least one image acquisition unit 110, or an optical tomography image acquired from a separate image acquisition device ( OCT image) further comprising a thickness calculator 124 for calculating the thickness of the cornea, wherein the intraocular pressure calculator 122, the thickness of the cornea calculated by the thickness calculator 124 and a predetermined correction factor is further used to calculate the intraocular pressure, and the information storage unit 123 may further store the corneal thickness calculated by the thickness calculation unit 124 into a database.

In addition, the calculation unit 120 analyzes the photographing date and time and intraocular pressure information stored in the information storage unit 123, and generates a warning message when at least one selected from the intraocular pressure itself or the amount of change in intraocular pressure according to the photographing date and time is greater than or equal to a predetermined standard. It may further include a warning output unit 125 to output.

In addition, at least two of the image acquisition unit 110 may be respectively disposed in at least two locations selected from the front, left, and right sides of the user's eyeball.

In addition, the wearing unit 130 has a curved surface corresponding to the face formed on one side so as to be in close contact with the user's face, and a housing 131 in which a plurality of the image acquisition units 110 are supported, the housing 131 . ) and the housing 131 may include a supporter 132 that is formed to be wearable on the user's ear or head to support the state in close contact with the user's face.

At this time, the housing 131 is formed such that the plurality of image acquisition units 110 are fixedly disposed at predetermined positions on the housing 131 , and at least four image acquisition units 110 are installed in the left eye of the user. The front side, the left side of the user's left eye, the front side of the user's right eye, and the right side of the user's right eye can be respectively arranged at positions including four places.

Alternatively, the housing 131 is formed such that the at least one image acquisition unit 110 is disposed so that it can be assembled and disassembled at a predetermined installation position on the housing 131 , wherein the image acquisition unit 110 is provided may be formed at a position including the front of the user's left eye, the left side of the user's left eye, the front of the user's right eye, and the right side of the user's right eye.

In addition, the supporter 132 may be formed in the form of a pair of temples over the ears or in the form of a band fixed around the head.

In addition, in the intraocular pressure measuring device 100, the calculating unit 120 is built into the wearing unit 130, or the calculating unit 120 is formed separately from the wearing unit 130 to transmit and receive data through wired/wireless communication. can be formed to

In addition, the intraocular pressure measuring device 100 is provided in a mobile phone including at least one camera, and the image acquisition unit 110 is implemented as the camera included in the mobile phone, and the mobile phone is equipped with the wearing part ( 130), and the operation unit 120 may be implemented as software installed in the mobile phone.

According to the present invention, based on the principle that the thickness of the eye tissue changes as the intraocular pressure changes, the change in the intraocular pressure can be measured with very high accuracy by measuring the structural variation of the cornea (change in the curvature of the corneal region and the thickness of the cornea). There is a big effect. In particular, at this time, since the cornea is disposed and exposed at the outermost part of the eye tissue, the structural variation can be easily measured with only an optical measuring device. It has a great effect that it is possible to easily measure changes in intraocular pressure. Of course, by being able to implement it as a personal portable mobile device, complex and large-scale equipment or equipment using expensive devices due to the concentration of the latest high-performance technology becomes unnecessary, resulting in greatly increasing the economic feasibility of the intraocular pressure measurement technology. There is also.

As described above, according to the present invention, it is possible to measure the intraocular pressure with sufficiently high accuracy while using an economical and convenient method, and accordingly, the general public, especially the patient themselves, can easily measure the intraocular pressure. In this way, as intraocular pressure is measured easily and frequently, it becomes possible to monitor the intraocular pressure very easily, which makes it possible to more smoothly diagnose the progress of ophthalmic diseases such as glaucoma, and ultimately, it is possible to significantly increase the treatment rate of these ophthalmic diseases. There is a leap forward effect that can lay the foundation for

1 is a schematic diagram of eye deformation according to changes in intraocular pressure (IOP);
2 is a schematic diagram of an artificial eye internal pressure control device, a schematic diagram of measuring intraocular pressure and a corneal surface tip, and a measurement result of an eye corneal surface tip change measured using the same.
4 is a measurement result of changes in eye characteristics according to changes in internal pressure of an artificial eye.
5 is a correlation between the intraocular pressure measured by the Goldmann Applanation Tonometer (GAT) method, the thickness of the central cornea, and the radius of curvature of the tip of the cornea;
6 is a block diagram of the intraocular pressure measuring device of the present invention.
7 is an embodiment of the intraocular pressure measuring device of the present invention.
8 is another embodiment of the intraocular pressure measuring device of the present invention.

Hereinafter, a portable intraocular pressure measuring device based on the structural variation of the cornea according to the present invention having the configuration as described above will be described in detail with reference to the accompanying drawings.

[1] Principle of measuring intraocular pressure of the present invention

IntraOcular Pressure (IOP) is a tension generated by the balance between the production and the outflow of aqueous humor. In general, the normal range of intraocular pressure is 10 mmHg ~ 21) mmHg, and the average intraocular pressure is about 15 mmHg. Therefore, continuous monitoring of intraocular pressure is very effective in determining the progress of ophthalmic diseases such as glaucoma and cataracts.

The principle of intraocular pressure measurement is based on Imbert-Fick's law, which is basically a law that calculates the internal pressure of a sphere filled with liquid and having infinitely thin thickness and no rigidity. That is, it is assumed that the eyeball is such a sphere, and when the eyeball is pressed with some force, the intraocular pressure is calculated on the principle that intraocular pressure = contact force/contact surface. At this time, the actual eyeball is surrounded by a thick cornea and there are some differences, such as not a perfect sphere, and this is corrected to some extent.

(A: corneal contact area, F: force applied to the corneal contact area, l: corneal radius of curvature, P _cp : pressure according to corneal characteristics, IOP: intraocular pressure, t: conversion constant)

That is, when measuring the existing intraocular pressure, a method of making a flat surface by pressing the eyeball in any way is used. Specifically, in the case of a contact type, by applying a force to the center of the cornea using a solid rod or air blow in the case of a non-contact type, a specific area is made flat, and the force required to achieve this condition is measured. , is to convert and estimate the intraocular pressure using the same formula as above.

However, it is known that variations according to the physical characteristics of the cornea (including bio-mechanical and geometrical properties) that are different for each race or human being are not considered in such an existing intraocular pressure measurement method. In addition, as described above, in the case of an otonometer based on the above principle, it is difficult to own and use by an individual because it is implemented as a complex and large device. However, there is a problem that reliability is not high in terms of accuracy.

In the present invention, a completely new approach is proposed to overcome the points presented as weaknesses of the various types of tonometric methods described above. That is, the eyeball is recognized as a system with an isolated elasticity, and when the internal pressure, that is, the intraocular pressure increases, the intraocular pressure is calculated using the principle that the eyeball is deformed to balance the internal pressure and the external atmospheric pressure. More specifically, when the intraocular pressure increases, the thickness of the ocular tissues decreases and the volume of the entire eyeball increases at the same time in order to achieve pressure balance between the inside and outside of the eyeball. Among various eye tissues, the cornea can be easily measured from the outside, so it can be inferred that intraocular pressure can be calculated using structural variations (specifically, changes in curvature or thickness) of the cornea.

1 shows a model of the eyeball, which is shown assuming that the eyeball is hollow and has a specific structure made of a material having elasticity such as rubber. As shown in FIG. 1(A) , the radius of curvature (RC, Radius of curvature) of the cornea in the case of _{initial intraocular pressure IOP 0 is RC 0} . If the intraocular pressure _{increases from IP 0} to IP ₁ for some reason, as the size of the entire eyeball increases, the radius of curvature of the cornea will increase from RC _{0 to RC 1 as shown in FIG.} If IOP ₂ decreases, the radius of curvature of the cornea will decrease from RC _{0 to RC 2 as shown in FIG. 1(C).} Therefore, if the radius of curvature of the cornea can be precisely measured using an appropriate optical method, it can be predicted that the variation in intraocular pressure can be estimated using the value.

At this time, as previously mentioned, when the eyeball is deformed according to a change in intraocular pressure, not only the radius of curvature of the cornea but also the thickness of the cornea is changed. In fact, previous in-vitro studies conducted using human eyeballs reported that the increase in corneal curvature, increase in strain at the tip of the cornea, and change in corneal thickness measured while applying pressure to the human eyeball were evident. (J. Hjortdal and PK Jensen, "In vitro measurement of corenal strain, thickness, and curvature using digital image processing" Acta Ophthalmol. Scand. 1995, 73: 5-11, Non-Patent Document 3) (N. Ethlers, T. Bramsen and S. Sperling, "Applanation tonomertry and cenetral corneal thickness", Acta Ophthamologica, 53, 34-43 (1975), Non-Patent Document 4). From the results of these studies, it can be concluded that intraocular pressure can be calculated well enough by measuring the structural variation of the cornea, which is the most exposed and convenient to measure among eye tissues.

[2] Reliability evaluation of the intraocular pressure measurement principle of the present invention

As such, it is necessary to check how accurate the result of calculating the intraocular pressure from the structural variation of the cornea is. That is, since the tonometer proposed in the present invention does not directly measure intraocular pressure, experimental results that can present comparison results with actual intraocular pressure are essential, and these experimental results are directly related to the reliability of the present invention.

In general, when a new tonometer is presented, it is compared with the results of measurement of intraocular pressure using the GAT (Glodmann Applanation Tonometer), which is a known and accepted tonometer in clinical practice. To explain the GAT in detail, it is a method of measuring the force when a certain area (3.06 mm in diameter) of the corneal surface is flattened using a specific type of prism and converting it into pressure (ISO 8612, Ophthalmic instrumentations &#8211) ; Tonometer, (2009)). According to the above standard, when measuring intraocular pressure in a method other than GAT, it is impossible to measure while directly changing the pressure in the human eye. Tests must be performed and the results submitted. That is, in such a clinical setting, intraocular pressure must be measured at once using the GAT and the proposed tonometer for each eye, and the process of determining the correlation coefficient by comparing the results of the two different methods obtained in this way to calculate the correlation coefficient is essential will be. On the other hand, the correlation coefficient shown by one human eye cannot be directly applied to another human eye with different physical-mechanical characteristics. Therefore, in order to develop a tonometer with better performance, it requires a very large number of impression measurement results for various races. This is difficult to implement because it takes a very long time and at the same time requires a very high cost, and therefore it is extremely difficult for a new tonometer to gain competitiveness compared to the existing tonometer.

To overcome the above difficulties, the test equipment for tonometer calibration was designed to physically secure the reliability of the measurement performance of the target tonometer. For example, PTB (Physikalisch-Technische Bundesanstalt), a German standards organization, designed and utilized a tonometer calibration device consisting of a pneumatic target mirror, a rotatable lever, and a balance to monitor the force generated by the pneumatic force. are doing The equipment for calibrating the tonometer is very sophisticated, so it is very difficult to move and install it, and it is inconvenient and only a skilled person can operate it. Also, more importantly, the cost of the entry-level orthodontic equipment is about US$ 30,000, which is very expensive, so it is economically inefficient. In addition, the tonometer calibration equipment contains a decisive disadvantage in that it is not easy to have traceability to absolute pressure standards such as a water column height or a sophisticated calibration pressure gauge. To solve these problems, various types of equipment for tonometer calibration have been devised, but so far, equipment for calibrating a tonometer with both economic feasibility, ease of use and reliability of measurement is not yet known.

One of the ways to solve the problems of existing methods to secure the reliability of clinical performance of the new tonometer is to create an artificial eye that can perfectly simulate the physical-mechanical properties and structural characteristics of the human eye- is a way to use it. More specifically, by using an artificial eye that perfectly mimics the human eye, the intraocular pressure is intentionally changed and the observed result and the simultaneously measured GAT result are directly compared to derive a correlation and the most appropriate correlation The coefficient is used to correct the results of the tonometer. The internal pressure of the artificial eye can be measured using an internal water column height or a precisely calibrated manometer with traceability. It will be possible to secure the performance reliability of the results of the tonometer.

However, until now, there has been no known method for fabricating an artificial eye that satisfies the above-mentioned conditions, that is, can perfectly mimic the physical-mechanical properties and structural characteristics of the human eye. In addition, even if it is possible to manufacture such an artificial eye, a method that can be stored for a long time while maintaining the characteristics of the artificial eye has not been reported, so this method could not be used to guarantee the performance and reliability of the tonometer.

In the present invention, this reliability evaluation was performed using an artificial eye manufactured based on Korean Patent Registration No. 1646222 (“Polymer-based artificial eye manufacturing method and apparatus”, 2016.08.01.). Figure 2 shows the experimental design for verifying the reliability of the IOP measurement principle of the present invention, Figure 3 shows the results. In more detail, it is as follows. 2(A) and (B) show that the artificial eye is equipped with a pressure regulating device and a pressure gauge to control the internal pressure of the artificial eye (corresponding to intraocular pressure). In addition, Fig. 2(A) is a schematic diagram of measuring intraocular pressure using a Goldmann Applanation Tonometer (GAT) prism, and Fig. 2(B) is an image of the cornea using optical coherent tomography (OCT) to use the principle of the present invention. Schematic diagrams of obtaining , respectively, are shown. In the present invention, the experiment was performed while changing the internal pressure of the artificial eye from 0 torr to 50 torr at intervals of 5 torr, and the OCT image obtained at this time is shown in FIG. 3 . The CCT (Central cornea thickness) of the artificial eye used at this time was 0.38 mm. Because the thickness of the cornea is so thin, it is difficult to detect it with the naked eye, but when the IOP is 0 and 50, the change in the corneal thickness can be understood with the naked eye to some extent.

4A to 4C are graphs showing the results measured in FIG. 3 as quantitative, ie, measurement results of changes in eye characteristics according to changes in pressure inside the artificial eye. In more detail, it is as follows.

4A is a graph of intraocular pressure (IOP_GAT) measured by the GAT method for artificial eye internal pressure, and is linearized with a red solid line. Here, the black solid line represents the ideal measured intraocular pressure, assuming that the internal pressure and the external intraocular pressure obtained by the GAT method are the same. As shown in Fig. 4a, the intraocular pressure measured by changing the internal pressure of the artificial eye shows very good linearity with IOP_GAT. More specifically, R ² (R square) is 0.998 and the slope is 0.863, so the theoretical IOP and It shows similar values. If the characteristics of the artificial eye (CCT and the elastic modulus of the eye tissue) are optimized, it can be expected that the slope, which is the theoretical value of the correlation between the theoretical model intraocular pressure and the externally measured intraocular pressure, will be closer to 1.0.

4B is a graph of central cornea thickness (CCT) versus intraocular pressure. As explained by the principle of FIG. 1 , it is possible to predict that an increase in the volume of the entire eyeball according to a change in internal pressure will ultimately result in a decrease in the thickness of the surface shell of the eyeball. This phenomenon will appear in the corneal region as well, and it can be confirmed experimentally that it will eventually appear as a decrease in the thickness of the center of the cornea. In particular, the CCT reduction ratio to internal pressure (=D(CCT)/CCT ₀ , excitation In D(CCT): the amount of change in CCT, CCT ₀ : CCT when the applied internal pressure is 0) shows a very good linear change with the externally observed intraocular pressure.

4C is a graph of the radius of curvature (RC) of the tip of the cornea with respect to the internal pressure of the artificial eye, and it can be seen that also shows a significant level of linearity with the internal pressure.

As such, the result measured using the artificial eye has the same tendency as the result measured using the excised human eye described above. That is, when the pressure inside the human eyeball increases, the thickness of the cornea decreases and the radius of curvature of the cornea increases at the same time. In order to infer a meaningful result from the above results, it is preferable to review the CCT change and RC change for the GAT method, which is considered a clinical standard for tonometry, rather than a comparative review of the internal pressure of the eye. . 5A and 5B show the correlation between intraocular pressure measured by the Goldmann Applanation Tonometer (GAT) method, the central corneal thickness (CCT), and the radius of curvature of the tip of the cornea (RC), respectively, where each point is an experimental observation result. The linear optimization results are shown by solid lines, respectively. In both cases, good linearity was shown in the IOP measurement range of 15 mmHg or higher. ^{(R 2} of CCT and RC is 0.985 and 0.914, respectively)

The above results confirm that the intraocular pressure measurement method proposed in the present invention, that is, the method of calculating the change in intraocular pressure using the characteristics of the eye cornea that can be measured externally such as CCT and RC in a non-contact manner, shows significantly significant reliability. Accordingly, it is sufficiently possible to routinely check changes in intraocular pressure in glaucoma patients using non-contact optical images.

[3] IOP measuring device of the present invention

As described above, the present invention calculates intraocular pressure by measuring changes in eye tissue according to changes in intraocular pressure, among others, structural changes (changes in curvature or thickness) of the cornea, which are exposed to the outside and are convenient to measure. That is, the equipment actually required for measurement in the present invention is just an optical measuring device having appropriate accuracy, which can be sufficiently realized even with a device having a level of complexity on the level of a portable mobile device.

6 is a block diagram of an intraocular pressure measuring device of the present invention, and FIGS. 7 and 8 are views showing an embodiment of the intraocular pressure measuring device of the present invention. As shown in FIG. 6 , the apparatus 100 for measuring intraocular pressure of the present invention includes an image acquisition unit 110 and a calculation unit 120 that substantially measure intraocular pressure, and the apparatus 100 for measuring intraocular pressure. It further includes a wearing part 130 that allows the user to easily wear it.

The image acquisition unit 110, as shown, is provided with a plurality of are arranged to be spaced apart from each other at a predetermined distance and angle, and at the same time, the image of the cornea is captured and acquired. Accordingly, the images obtained by the plurality of image acquisition units 110 are obtained in different angles and distances from each other. In fact, when the image acquisition unit 110 is to be implemented, any device capable of acquiring an image, such as a generally used camera or CCD device, may be used. On the other hand, in FIG. 7, the three image acquisition units 110 are shown as being disposed on the front, left side, and right side of the user's eyeball. Since it is difficult, in practice, two may be arranged on the front and left side of the user's eye, or two may be arranged on the front and right side of the user's eye. Alternatively, it is not necessarily required to be disposed on the front/side, and of course, it may be disposed in various ways as needed, such as disposed at a 45 degree angle with respect to the front. 8 shows an example in which a total of eight image acquisition units 110 are disposed, one on each front side of the user's left/right eye and three on the left/right side. In particular, the image disposed on the left/right side The acquisition unit 110 shows an example in which the front side of the eyeball, the upwardly inclined side, and the downwardly inclined side are arranged so as to be photographed at three different angles. As such, the arrangement of the image acquisition unit 110 may be variously changed according to user needs. However, considering the ease of calculating the curvature, for one user's eye, it is preferable that at least two of the image acquisition unit 110 are respectively arranged in at least two places selected from the front, left, and right side of the user's eye. do.

The calculating unit 120 may basically include a curvature calculating unit 121 , an intraocular pressure calculating unit 122 , and a chastity storage unit 123 . In addition to this, as shown in FIG. 6 , it may further include a thickness calculating unit 124 and a warning output unit 125 . Each part will be described in detail as follows.

The curvature calculator 121 calculates the curvature of the cornea using a plurality of images simultaneously acquired by each of the image acquisition units 110 . More specifically, as the image acquisition units 110 are spaced apart from each other at a predetermined distance and angle, the curvature is calculated by using a shape difference generated between images of a plurality of corneas taken at the same time. In this case, the curvature calculating unit 121 may obtain a corneal tip shape from the image of the cornea acquired by the image acquiring unit 110 , and calculate the curvature by using a plurality of the corneal tip shapes.

The intraocular pressure calculator 122 calculates the intraocular pressure using the corneal curvature calculated by the curvature calculator 121 and a predetermined correction factor. As explained in [2] , since the change in intraocular pressure has a direct correlation with the change in corneal curvature, a simple relational expression such as [Intraocular pressure = correction factor x corneal radius of curvature] can be created. For example, based on FIG. 5B , the correction factor may be 12.15 μm/mmHg. That is, as long as the curvature of the cornea is correctly calculated from the images, the intraocular pressure can be calculated very easily from this.

The information storage unit 123 serves to store the corneal curvature calculated by the curvature calculating unit 121 and the intraocular pressure calculated by the intraocular pressure calculating unit 122 into a database at the time of photographing stored in the image. . As described above, the intraocular pressure measuring apparatus 100 of the present invention has the purpose of allowing patients with ophthalmic diseases such as glaucoma to easily measure and monitor their own intraocular pressure from time to time, so the amount of change in intraocular pressure according to the seal is measured. It goes without saying that it is necessary to be able to check. Meanwhile, since recent digital photographing devices basically record photographing date and time information in an image file, it is not difficult at all to extract photographing date and time information from an image. In consideration of these matters, it is desirable that the information storage unit 123 link the photographing date and time and information such as curvature and intraocular pressure at that time to form a database.

The thickness calculator 124 serves to calculate the thickness of the cornea. At this time, if the image acquisition unit 110 can acquire a sufficiently high-quality image, the thickness calculator 124 may use at least one image acquired from the at least one image acquisition unit 110 . However, since the cornea itself is a very thin object, a fairly high-performance image acquisition device may be required to accurately calculate the thickness of the cornea. Considering this point, the thickness calculating unit 124 may calculate the thickness of the cornea using an optical tomography image (OCT image) obtained from a separate image acquisition device other than the image acquisition unit 110 . . The device for acquiring an optical tomography image is quite large and complicated, so it may be difficult to be realized as a portable device. However, since the OCT equipment is being miniaturized rapidly through various studies in recent years, the thickness calculation is performed in the intraocular pressure measuring device 100 in the future. The optical tomography image acquisition device of the unit 124 may be included. However, since the OCT equipment is not miniaturized enough to be portable at the present time, the thickness calculator 124 may be configured to calculate the corneal thickness by receiving the optical tomography image obtained using a separate OCT equipment. Of course, since the intraocular pressure measuring apparatus 100 of the present invention can calculate the intraocular pressure with a desired degree of accuracy only with the curvature of the cornea, it is not essential to measure the thickness of the cornea.

When the calculating unit 120 further includes the thickness calculating unit 124 , the intraocular pressure calculating unit 122 further uses the thickness of the cornea calculated by the thickness calculating unit 124 and a predetermined correction factor to further use the intraocular pressure. can be calculated. When the corneal curvature is calculated, the intraocular pressure is already calculated. However, if the corneal thickness is further calculated, the accuracy of the calculated intraocular pressure may be further improved. Of course, in this case, it is preferable that the information storage unit 123 stores the photographing date and time, the curvature of the cornea, and the thickness of the cornea as well as the intraocular pressure into a database.

The warning output unit 125 analyzes the photographing date and time and intraocular pressure information stored in the information storage unit 123, and outputs a warning message to warn the user if necessary. In this case, the criteria for outputting the warning message may be determined in various ways, and a specific example may be the intraocular pressure itself. That is, when the intraocular pressure is measured above a predetermined standard, a warning message is outputted immediately. Alternatively, the amount of change in intraocular pressure according to the date and time of shooting can be used. In this case, the degree of change in intraocular pressure according to the seal is analyzed, and a warning message indicating that the condition worsens when the intraocular pressure rises rapidly according to the seal or exceeds a predetermined standard. may be output.

The wearing unit 130 not only serves to allow a user to easily wear the intraocular pressure measuring device 100 as shown in FIG. 7 , but also acquires the image by the wearing unit 130 . It serves to allow the unit 100 to be easily disposed at a predetermined distance and direction. Considering this role, it is natural that the image acquisition unit 110 must be provided in the wearing unit 130 . However, the calculating unit 120 does not necessarily have to be provided in the wearing unit 130 , that is, the calculating unit 120 may be built into the wearing unit 130 , but the calculating unit 120 is the wearing unit 130 . It may be formed separately from 130 to transmit and receive data through wired/wireless communication. In the latter case, the operation unit 120 may be implemented in the form of software installed on a separate PC or a mobile device such as a mobile phone.

The wearing unit 130 has a curved surface corresponding to the face formed on one side so as to be in close contact with the user's face, and a housing 131 in which a plurality of the image acquisition units 110 are supported and the housing 131 . and a supporter 132 that is connected to the housing 131 to support a state in which the housing 131 is in close contact with the user's face and is wearable on the user's ear or head. The supporter 132 may be formed in the form of a band to be fixed around the head as shown in the drawing, or may be formed in the form of a pair of temples that are worn over the ears. Any form is free

As described above, the image acquisition unit 110 is preferably disposed on the front and left/right sides of the user's eyeball. Since the user's eyes are always two, the plurality of the image acquisition unit 110 includes four locations: the front of the user's left eye, the left side of the user's left eye, the front of the user's right eye, and the right side of the user's right eye It must be able to be placed in position.

At this time, if the image acquisition unit 110 is implemented as a CCD device, the housing 131 allows the image acquisition unit 110 to be fixedly disposed on the housing 131 to provide the image acquisition unit 110 . and the wearing part 130 may be integrally formed, and FIG. 7 shows just such an embodiment. Specifically, the housing 131 is formed such that the plurality of image acquisition units 110 are fixedly arranged at predetermined positions on the housing 131 . In this case, at least four image acquisition units 110 are respectively disposed at positions including the front of the user's left eye, the left side of the user's left eye, the front of the user's right eye, and the right side of the user's right eye. Of course, in addition to these four places, the image acquisition unit 110 is further provided at a position such as a 45 degree position between the front and side surfaces, as exemplified above, so as to acquire images from various angles. In this case, the intraocular pressure measuring apparatus 100 may be made, for example, in a shape similar to a currently used face-wearing VR device.

Alternatively, if the image acquisition unit 110 is implemented as a mobile phone camera, the housing 131 is formed so that the image acquisition unit 110, which is a separate and independent unit, can be inserted into or removed from the housing 131 . can be Specifically, the at least one image acquisition unit 110 is formed so as to be reassembled and disassembled at a predetermined location on the housing 131 . In this case, the location of the image acquisition unit 110 is formed in a position including the front of the user's left eye, the left side of the user's left eye, the front of the user's right eye, and the right side of the user's right eye. As in the previous embodiment, it is natural that the provided position may be further provided at a different angle.

To elaborate on the latter embodiment, the intraocular pressure measuring device 100 of the present invention requires only an optical imaging device and an integrated circuit for various calculations in actual implementation, so these parts are already provided. It can also be implemented using a mobile phone. That is, in the case of a recently produced and distributed mobile phone, at least one camera is included, and the image acquisition unit 110 is implemented with the camera included in the mobile phone, and the mobile phone is provided with a predetermined portion of the wearing unit 130 . It can be provided on location. Since a predetermined location is formed in the wearing unit 130, the user inserts the mobile phone into the provided location to take a picture, takes out the mobile phone, puts the mobile phone in another location, and takes pictures again. can be obtained. In addition, the calculating unit 120 can be implemented in the form of software installed in the mobile phone. In this way, the user can install the calculating unit 120 in his or her mobile phone in the form of simply downloading the app, and the mobile phone camera You can easily self-measure your intraocular pressure by taking pictures of your own eyeballs.

As such, the intraocular pressure measuring device 100 of the present invention measures the change in intraocular pressure by measuring the structural variation of the cornea, that is, for example, the radius of curvature of the tip of the cornea or the thickness of the cornea using an optical measuring device in a non-contact manner. . This has the advantage of significantly reducing the burden of measurement on the patient because direct contact with the eye is avoided. In addition, since practically necessary parts are an optical imaging device and an integrated circuit for various calculations, it is also suitable for portable miniaturization. It is possible to take measurements on your own from time to time without visiting. In addition, it is possible to easily monitor the state of intraocular pressure by itself using a database or a warning output function of the operation unit 120, thereby preventing problems such as missing a treatment time.

The present invention is not limited to the above-described embodiments, and the scope of application is varied, and anyone with ordinary knowledge in the field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims It goes without saying that various modifications are possible.

100: intraocular pressure measuring device
110: image acquisition unit 120: calculation unit
121: curvature calculating unit 122: intraocular pressure calculating unit
123: information storage unit 124: thickness calculation unit
125: warning output unit
130: wear part
131: housing 132: supporter

Claims (12)

a plurality of image acquisition units 110 arranged to be spaced apart from each other at a predetermined distance and angle, and obtained by photographing images of the cornea at the same time;
Curvature calculating unit 121 for calculating the curvature of the cornea using a plurality of images simultaneously acquired by each of the image acquisition unit 110;
an intraocular pressure calculator 122 for calculating intraocular pressure using the curvature of the cornea calculated by the curvature calculator 121 and a predetermined correction factor;
Calculating unit 120 including an information storage unit 123 for storing the photographing date and time stored in the image, the curvature of the cornea calculated by the curvature calculating unit 121 and the intraocular pressure calculated by the intraocular pressure calculating unit 122 into a database );
a wearing unit 130 that supports the plurality of image acquisition units 110 and is formed to be wearable on the user's face;
An intraocular pressure measuring device comprising a.
According to claim 1, wherein the curvature calculating unit 121,
The apparatus for measuring intraocular pressure, characterized in that the image acquisition unit 110 is spaced apart from each other at a predetermined distance and angle, and the curvature is calculated using a shape difference generated between images of a plurality of corneas taken at the same time.
According to claim 2, wherein the curvature calculating unit 121,
Obtaining the shape of the tip of the cornea from the image of the cornea acquired in the image acquisition unit 110,
An apparatus for measuring intraocular pressure, characterized in that the curvature is calculated using a plurality of shape of the tip of the cornea.
According to claim 1, wherein the intraocular pressure measuring device 100,
The operation unit 120 calculates the thickness of the cornea using at least one image acquired by the at least one image acquisition unit 110 or an optical tomography image (OCT image) acquired from a separate image acquisition device. It further includes a thickness calculation unit 124 to calculate,
The intraocular pressure calculating unit 122 calculates the intraocular pressure further using the corneal thickness calculated by the thickness calculating unit 124 and a predetermined correction factor,
The information storage unit 123, the intraocular pressure measuring device, characterized in that the database further stores the thickness of the cornea calculated by the thickness calculation unit (124).
According to claim 1, wherein the operation unit 120,
A warning output unit 125 that analyzes the photographing date and time and intraocular pressure information stored in the information storage unit 123, and outputs a warning message when at least one selected from the intraocular pressure itself or the amount of change in intraocular pressure according to the photographing date and time is greater than or equal to a predetermined standard. An intraocular pressure measuring device, characterized in that it further comprises.
According to claim 1, wherein the image acquisition unit 110,
At least two devices for measuring intraocular pressure, characterized in that each is disposed in at least two locations selected from the front, left, and right side of the user's eyeball.
According to claim 1, wherein the wearing part 130,
A housing 131 having a curved surface corresponding to the face formed on one side so as to be in close contact with the user's face, and having a plurality of the image acquisition units 110 supported therein;
A supporter 132 connected to the housing 131 to support a state in which the housing 131 is in close contact with the user's face and is wearable on the user's ear or head.
An intraocular pressure measuring device comprising a.
According to claim 7, wherein the housing (131),
A plurality of the image acquisition unit 110 is formed to be fixedly disposed at a predetermined position on the housing 131,
At least four of the image acquisition unit 110 are respectively disposed at positions including the front of the user's left eye, the left side of the user's left eye, the front of the user's right eye, and the right side of the user's right eye. an intraocular pressure measuring device.
According to claim 7, wherein the housing (131),
The at least one image acquisition unit 110 is formed so as to be disassembled and disassembled at a predetermined location on the housing 131,
Intraocular pressure, characterized in that the provided position of the image acquisition unit 110 is formed in a position including four places: the front of the user's left eye, the left side of the user's left eye, the front of the user's right eye, and the right side of the user's right eye measuring device.
According to claim 7, wherein the supporter (132),
An intraocular pressure measuring device, characterized in that it is formed in the form of a pair of temples over the ears or in the form of a band fixed around the head.
According to claim 1, wherein the intraocular pressure measuring device 100,
The calculating unit 120 is built into the wearing unit 130, or
The apparatus for measuring intraocular pressure, characterized in that the calculating unit 120 is formed separately from the wearing unit 130 to transmit and receive data through wired/wireless communication.
The method of claim 9, wherein the intraocular pressure measuring device 100,
As a form provided in a mobile phone including at least one camera,
The image acquisition unit 110 is implemented with the camera included in the mobile phone, the mobile phone is provided at a predetermined location of the wearing unit 130,
The calculation unit 120 is an intraocular pressure measuring device, characterized in that implemented as software installed in the mobile phone.

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