Diagnostic method and diagnostic device for distinguishing dry eye types

Abstract

The present invention relates to a diagnostic method and a diagnostic apparatus for differentiating a dry eye type. The method comprises: (a) a step of examining a tear film break-up time point and position, photographing a cornea of an eye of a subject to be examined and examining at least one tear film break-up time point in time series as time elapses, at which a break-up appearance is determined from an image of the photographed cornea reflection; (b) a step of examining a corneal surface temperature, measuring the corneal surface temperature of the subject to be examined using a thermal imaging camera, and examining a change in the surface temperature of the cornea over time in time series, which is performed simultaneously with photographing a tear film of the eye; (c) a step of mapping the at least one tear film break-up time point and the change in the surface temperature of the cornea based on time and comparing a position of the at least one tear film break-up time point with a position of the surface temperature of the cornea; and (d) a step of diagnosing a type of dry eye, in a mapping result of step (c), based on any one position of the at least one tear film break-up time point and a position of a change time point of the surface temperature of the cornea corresponding thereto, a type of dry eye is diagnosed.

Description

Technical Field

[0001] The present invention relates to diagnostic methods and devices for differentiating types of dry eye syndrome, and more specifically, to such diagnostic methods and devices for differentiating types of dry eye syndrome that can determine the type of dry eye syndrome based on images reflected from the cornea and the time of change in corneal surface temperature using optical and thermal imaging cameras. Background Technology

[0002] Dry eye syndrome is an ocular surface disease caused by quantitative / qualitative abnormalities in the tear film. The tear film consists of three layers: the mucus layer, the aqueous layer, and the lipid layer. The aqueous layer of the tear film accounts for approximately 95% of the total tear fluid, and its main function is to provide moisture. The mucus layer forms the innermost layer of the tear film, allowing the aqueous layer to adhere well to the ocular surface and retain moisture. The lipid layer forms the outermost layer of the tear film, and because the surface of the aqueous layer is covered by the lipid layer, the lipid layer stabilizes the air / tear film boundary and prevents the aqueous layer from evaporating.

[0003] Quantitative or qualitative abnormalities in any component of the tear film (i.e., the mucus layer, aqueous layer, and lipid layer) can lead to tear film instability and dry eye syndrome. Based on the condition of the abnormal tear film layer and its etiology, dry eye syndrome can be classified into several types. For example... Figure 1 As shown, dry eye syndrome types include aqueous layer deficiency dry eye syndrome, mucous layer deficiency dry eye syndrome, and lipid layer deficiency dry eye syndrome.

[0004] Aqueous-layer deficiency dry eye is a type of dry eye caused by an insufficient amount of the aqueous layer, a component of the tear film that protects the ocular surface and provides moisture. Since the aqueous layer comprises approximately 95% of total tears, a decrease in total tear volume compared to normal can lead to a diagnosis of aqueous-layer deficiency dry eye. Methods for measuring tear volume include the Schirmer Test or similar Strip Meniscometry methods, which measure tear volume by placing the tip of a strip of paper or tube on the eyelid margin and conjunctiva, as well as optical coherence tomography (OCT), which directly measures the height and area of ​​the tear film. Therefore, in clinical practice, aqueous-layer deficiency dry eye can be diagnosed using various diagnostic devices.

[0005] Mucus-deficiency dry eye is a type of dry eye characterized by insufficient mucus layer in the tear film, resulting in poor adhesion of the aqueous layer to the ocular surface, particularly the cornea (decreased wettability). This leads to reduced tear film stability and uneven tear film distribution across the ocular surface. The mucus layer of the tear film is secreted by goblet cells located between the epithelial cells of the conjunctiva. However, due to the lack of diagnostic equipment to measure the amount of mucus layer, mucus-deficiency dry eye is predicted indirectly in clinical practice. To indirectly confirm mucus deficiency, tear film breakup time is measured based on the mechanism of decreased tear film stability and shortened tear film breakup time in the presence of mucus layer deficiency. A shortened tear film breakup time is predicted to indicate mucus-deficiency dry eye. However, since tear film breakup time is also shortened in lipid-deficiency dry eye, there is no way to completely distinguish between mucus-deficiency dry eye and other types of dry eye. Furthermore, although mucus deficiency can be indirectly predicted by confirming a decrease in goblet cell density as measured by conjunctival impression cytology, conjunctival impression cytology is an invasive test and is difficult to routinely perform in the differential diagnosis of dry eye. Moreover, since it measures the decrease in goblet cell density immediately after a decrease in mucus secretion, a decrease in mucus production, or an excess of mucus secretion, it cannot confirm the actual degree of mucus secretion.

[0006] Lipid-deficient dry eye is caused by increased tear evaporation due to quantitative / qualitative abnormalities in the outermost lipid layer of the tear film. The lipid layer of the tear film is produced by the meibomian glands on the inner side of the eyelids and supplied to the ocular surface through the meibomian gland vents at the eyelid margin. Increased tear evaporation can be confirmed by measuring the tear evaporation rate using an evaporator, but there are no commercially available tear evaporation measurement devices in clinical practice. Clinically, dry eye signs of increased tear evaporation can be diagnosed by confirming the presence of meibomian gland dysfunction, a representative disease of increased tear evaporation, but not all meibomian gland dysfunction is associated with dry eye. Recently, a diagnostic device for measuring lipid layer thickness has been commercialized and is available; however, the reproducibility of lipid layer thickness measurements is low. Even with an increase in lipid components that cannot function properly due to changes in lipid composition, a thick lipid layer can still be measured. Furthermore, there is a limitation in measuring a thicker lipid layer even when the tear film is contaminated with cosmetics or the aqueous layer is relatively thin, thus the lipid layer cannot be evenly spread across the ocular surface.

[0007] (Patent Document 1) (Korean Patent Publication No. 10-2018-0072911, July 2, 2018) Summary of the Invention

[0008] Technical issues

[0009] The purpose of this invention is to provide a diagnostic method and device for differentiating types of dry eye syndrome, wherein, using an optical camera and a thermal imaging camera, the type of dry eye syndrome can be determined based on images reflected from the cornea and the time of change in corneal surface temperature.

[0010] The purpose of this invention is not limited to the above-described purposes, and other unmentioned purposes will be clearly understood by those skilled in the art from the following description.

[0011] Technical solution

[0012] To achieve the above objectives, a diagnostic method for distinguishing types of dry eye according to an embodiment of the present invention includes: (a) examining the tear film breakup time point and location by photographing the cornea of ​​a subject's eye and examining at least one tear film breakup time point in a time sequence, at which the reflected image from the photographed cornea is confirmed to have broken over time; (b) examining the surface temperature of the cornea of ​​the subject to be evaluated by measuring the surface temperature of the cornea in a time sequence using a thermal imaging camera, thereby examining the surface temperature of the cornea, the examination of the surface temperature of the cornea being performed simultaneously with the photographing of the tear film of the eye; (c) mapping the tear film breakup time point and the surface temperature change of the cornea based on time to compare the time points of the tear film breakup time point and the surface temperature change of the cornea; and (d) diagnosing the type of dry eye based on any one of the tear film breakup time points and the location of the corresponding time point of the surface temperature change of the cornea in the mapping result of step (c).

[0013] Here, in step (a), an optical camera can be used to photograph the cornea of ​​the eye, and the area and location of the tear film break can be calculated based on the image reflected from the cornea as the area and time of the break, and the time can be confirmed.

[0014] Here, in step (d), if the initial point of the tear film breakup time corresponds to the time point with the maximum decreasing slope among the points of temperature change of the cornea captured by the thermal imaging camera, it can be determined as evaporative dry eye syndrome. And if the temperature change of the cornea captured by the thermal imaging camera decreases linearly after the point of tear film breakup is observed, and then decreases sharply after a certain period of time, such that the temperature change of the cornea is observed later than the initial point of tear film breakup time relative to the initial point of tear film breakup time, it can be determined as mucus-deficiency dry eye syndrome.

[0015] A diagnostic device for distinguishing types of dry eye syndrome according to an embodiment of the present invention includes: an optical camera for capturing images of an eye; a thermal imaging camera for acquiring thermal images of the eye and measuring temperature changes of the eye; and a control unit configured to determine the type of dry eye syndrome by mapping and analyzing the images captured by the optical camera and the thermal images acquired by the thermal imaging camera.

[0016] The control unit may include: a mapping unit for mapping the temporal change state of the tear film breakup time point obtained by the optical camera and the temporal change state of the corneal surface temperature obtained by the thermal imaging camera based on time; and a dry eye type determination unit for determining the type of dry eye by comparing the initial time point of the tear film breakup time point and the temperature change time point captured by the thermal imaging camera from two mapped images.

[0017] Beneficial effects

[0018] The diagnostic method and diagnostic device for differentiating dry eye types according to the present invention use an optical camera to photograph the cornea of ​​the eye and examine the time series of tear film breakup time points. At the same time, a thermal imaging camera is used to examine the surface temperature of the cornea of ​​the object to be evaluated. Based on time mapping of these two indicators, the type of dry eye can be more accurately determined based on the location of the tear film breakup time point and the location of the corneal surface temperature change time point.

[0019] The effects of the present invention are not limited to those described above, and other unmentioned effects will be clearly understood by those skilled in the art from the following description. Attached Figure Description

[0020] Figure 1 This is a diagram showing the types of dry eye syndrome.

[0021] Figure 2 A flowchart illustrating a diagnostic method for differentiating types of dry eye syndrome according to an example of the present invention is shown.

[0022] Figure 3 Graphs and images of corneal tear film breakup and temperature changes in evaporative dry eye syndrome obtained through examples of the present invention are shown.

[0023] Figure 4 Charts and images of corneal tear film breakup and temperature changes in mucus-deficiency dry eye syndrome, obtained through examples of the present invention, are shown.

[0024] Figure 5 A block diagram of a device for diagnosing dry eye syndrome types according to an example of the present invention is shown.

[0025] Figure 6Experimental results related to the heat of vaporization are shown. Detailed Implementation

[0026] In the following description, preferred embodiments of the invention will be illustrated in detail with reference to the accompanying drawings. It should be noted that, in this context, the same components are indicated by the same reference numerals wherever possible. Furthermore, detailed descriptions of well-known functions and constructions that may obscure the essence of the invention will be omitted. For the same reason, some components are exaggerated, omitted, or shown schematically in the drawings.

[0027] Furthermore, throughout the instruction manual, when a section "includes" a component, it means that other components may be included, rather than excluded, unless otherwise specifically stated otherwise. Also, throughout the instruction manual, "above" refers to being above or below the target part, and does not necessarily mean being above in the direction of gravity.

[0028] refer to Figures 2 to 4 According to an embodiment of the present invention, the diagnostic method for distinguishing types of dry eye includes the steps of checking the tear film breakup time point (S100), checking the corneal surface temperature (S200), comparing the tear film breakup time point with the corneal surface temperature change time point (S300), and diagnosing the type of dry eye (S400).

[0029] In the step (S100) of checking the tear film breakup time point, the cornea of ​​the subject's eye is photographed, and at least one tear film breakup time point is identified chronologically at which the image reflected from the photographed cornea shows a breakup. At this time, the cornea of ​​the eye is photographed using an optical camera, and based on the area and time of the breakup in the image reflected from the cornea, the area and location of the tear film breakup are calculated, and the time is confirmed.

[0030] The step of checking the corneal surface temperature (S200) is performed simultaneously with photographing the tear film of the eye, and the surface temperature of the cornea of ​​the object to be evaluated is checked using a thermal imaging camera to confirm the change of corneal surface temperature over time in chronological order. In this case, the thermal imaging camera can be arranged adjacent to the optical camera.

[0031] In the step (S300) of comparing the tear film breakup time point with the corneal surface temperature change time point, the tear film breakup time point is compared with the corneal surface temperature change time point by mapping the tear film breakup time point and the corneal surface temperature change based on time.

[0032] In the step (S400) of diagnosing the type of dry eye, the type of dry eye is diagnosed based on any one of the tear film breakup time points and the corresponding corneal surface temperature change points.

[0033] If the initial tear film breakup time point (A) that determines the tear film breakup time point corresponds to the time point (B) with the maximum downward slope among the corneal temperature change points captured by a thermal imaging camera, then it can be identified as evaporative dry eye syndrome.

[0034] In evaporative dry eye, as moisture evaporates from the cornea, the surrounding evaporative heat is absorbed, and the temperature decreases. The absorption of evaporative heat over time is greatest at the onset of water evaporation, resulting in the largest measured temperature change. Therefore, the moment when tear evaporation begins can be predicted by measuring the temperature change on the corneal surface.

[0035] If the corneal temperature change captured by a thermal imaging camera decreases linearly after the observed tear film breakup time point (A), and then decreases sharply (C) after a certain time period (Δt), such that the sharp temperature change of the cornea is observed later than the initial point (A) relative to the tear film breakup time point, it is identified as mucinous dry eye syndrome. In mucinous dry eye syndrome, the tear film is destroyed because it does not adhere properly to the corneal surface, not because of tear evaporation. Therefore, compared to evaporative dry eye syndrome, which destroys the tear film due to tear evaporation, the temperature decrease due to the absorption of evaporative heat is less, or the temperature decrease occurs after the tear film is destroyed.

[0036] refer to Figure 5 According to an embodiment of the present invention, a diagnostic device for distinguishing types of dry eye syndrome includes an optical camera 110, a thermal imaging camera 120, and a control unit 130.

[0037] The optical camera 110 is used to capture images of the corneal surface.

[0038] The thermal imaging camera 120 is used to obtain thermal images of the corneal surface and measure (capture) temperature changes on the corneal surface.

[0039] The control unit 130 determines the type of dry eye by mapping and analyzing the image obtained by the optical camera 110 and the thermal image obtained by the thermal imaging camera 120, and may be provided with a mapping unit 131 and a dry eye type determination unit 132.

[0040] The mapping unit 131 maps the temporal changes of the tear film breakup time points obtained from the optical camera 110 and the temporal changes of the corneal surface temperature obtained from the thermal imaging camera 120 based on time. The dry eye type determination unit 132 determines the type of dry eye by comparing the initial time point of the tear film breakup time points with the temperature change time points captured by the thermal imaging camera 120 from the two mapped images.

[0041] Figure 6 Experimental results related to the heat of vaporization are shown.

[0042] As experimental conditions, the ambient temperature of the corneal surface was 10℃, the internal temperature of the eyeball was 34℃, the thickness of the tear film before rupture was 10μm, the size of the corneal surface was 10mm×10mm, and the rupture area was 1mm×1mm.

[0043] like Figure 6 As shown, it has been confirmed that the rate of heat transfer through evaporation increases as the tear film breakup thickness decreases.

[0044] For example, when the surface temperature of the tear film on the corneal surface is 28°C, it was observed that when tear evaporation occurs in a tear film with a thickness of 5 μm, the corneal surface temperature drops to 22°C. Furthermore, it was observed that when tear evaporation occurs in a tear film with a thickness of 7 μm, the corneal surface temperature drops to 25.5°C. Generally, the evaporative thermal conductivity through a thin liquid film can be determined by… Figure 6 The equation is defined as shown.

[0045] The diagnostic method and diagnostic device for differentiating dry eye types according to the present invention use an optical camera to photograph the cornea of ​​the eye and examine the time series of tear film breakup time points. At the same time, a thermal imaging camera is used to examine the corneal surface temperature of the subject to be evaluated, and the two indicators are mapped based on time, thereby enabling a more accurate determination of the dry eye type based on the location of the tear film breakup time point and the location of the corneal surface temperature change time point.

[0046] Although the invention has been specifically described with reference to particular embodiments, it will be apparent to those skilled in the art that such description is merely a preferred embodiment, and the scope of the invention is not limited thereto. It will be apparent to those skilled in the art that other modifications based on the technical concept of the invention can be implemented in addition to the embodiments disclosed herein.

Claims

1. A diagnostic device for differentiating types of dry eye syndrome, comprising: An optical camera, used to capture images of the eye; A thermal imaging camera, used to acquire thermal images of the eye and measure temperature changes in the eye; as well as A control unit is configured to determine the type of dry eye by mapping and analyzing the image captured by the optical camera and the thermal image obtained by the thermal imaging camera, wherein... The tear film breakup time and location are examined by using the optical camera to photograph the cornea of ​​the subject's eye and examining at least one tear film breakup time point in time sequence, at which the reflected image from the photographed cornea is confirmed to have broken up over time; The surface temperature of the cornea is examined by using the thermal imaging camera to measure the surface temperature of the cornea of ​​the subject being evaluated simultaneously with the tear film of the eye, thereby examining the change of the surface temperature of the cornea over time in a time series. The tear film breakup time point and the change in the surface temperature of the cornea are mapped based on time to compare the tear film breakup time point and the time point of the change in the surface temperature of the cornea. In the mapping results, the type of dry eye is diagnosed based on any one of the tear film breakup time points and the location of the corresponding corneal surface temperature change time point; If the initial tear film breakup time point corresponds to the time point with the maximum downward slope among the temperature change points of the cornea captured by the thermal imaging camera, then it is determined to be evaporative dry eye syndrome. If the temperature change of the cornea as captured by the thermal imaging camera decreases linearly after the time point at which the tear film breaks down, and then decreases sharply after a certain period of time, such that the temperature change of the cornea is observed later than the initial point of the tear film breakup time point relative to the initial point of the tear film breakup time point, then it is determined to be mucus-deficiency dry eye syndrome.

2. The diagnostic device for differentiating types of dry eye syndrome according to claim 1, wherein, The optical camera is used to photograph the cornea of ​​the eye, and the area and location of tear film rupture are calculated based on the area and time of the rupture as determined by the image reflected from the cornea, and the time is confirmed.

Images