Cognitive impairment assessment method based on OCT imaging technology

Abstract

The invention discloses a cognitive impairment assessment method based on an OCT imaging technology, and belongs to the technical field of cognitive impairment prediction. According to the cognitive impairment prediction method based on the OCT imaging technology, the result prediction accuracy is high, the phenomena of missed diagnosis and indefinite diagnosis are effectively reduced / avoided, and the method has important practical value for early discovery of cognitive impairment; the method has the advantages that lumbar puncture does not need to be carried out on a person to be detected, the method is non-invasive, less pain is brought to the person to be detected, the safety is high, popularization of cognitive impairment screening is facilitated, high-risk people with cognitive impairment can be judged, early intervention on the patient with cognitive impairment is further realized, and the onset progress of cognitive impairment is delayed; the method is simple and easy to operate, and many examinations and measurements can be realized by setting parameters for instruments and equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of cognitive dysfunction prediction, and in particular to a cognitive dysfunction assessment method based on OCT imaging technology. Background Art

[0002] Cognitive impairment is a pathological process in which the brain's advanced intelligence processing related to learning, memory, and thinking and judgment becomes abnormal, leading to severe learning and memory disorders, and changes such as aphasia. Cognition involves a series of psychological and social behaviors such as learning, memory, language, and thinking. Any factor that causes abnormalities in the function and structure of the cerebral cortex will lead to cognitive impairment. Because brain function is complex and different types of cognitive impairment are interrelated, cognitive problems in one aspect can cause cognitive impairment in one or even several other aspects. Therefore, cognitive impairment is one of the most difficult problems in the diagnosis and treatment of brain diseases.

[0003] Alzheimer's disease (AD) is a neurodegenerative disease with an increasing incidence rate with age. According to the World Health Organization's 2021 report on the epidemiology of Alzheimer's disease, more than 55 million people worldwide are currently suffering from the disease, and the number of patients is expected to reach 139 million by 2050. The retina is a central nervous system tissue formed during the development of the brain, and the earliest disease-specific signs, namely beta-amyloid (Aβ) plaques, can be detected in the retina of patients with Alzheimer's disease. In addition, there is a normal physiological area on the retina, namely the macula, which is rich in lutein and darker than the surrounding retina. The depression in the center of the macula is called the fovea. The pathological relationship between the retina and Alzheimer's disease has promoted the development of imaging tools, and optical coherence tomography (OCT) is a technology used for non-invasive detection of Alzheimer's disease. Through the detection of biomarkers, it promotes the progress of early diagnosis of Alzheimer's disease.

[0004] There are two potential pathological markers for the diagnosis of AD: the progressive accumulation of β-amyloid (Aβ) plaques and intracellular neurofibrillary tangles (NFTs), extracellular Aβ plaque deposition, and intracellular tau protein hyperphosphorylation leading to neurofibrillary tangles (NFTs). These symptoms can appear 10-15 years before the onset of the disease. Early diagnosis of Alzheimer's disease can be achieved through the detection of pathological markers. The current general method for AD diagnosis is still to use lumbar puncture to detect the content of pathological markers. Since this method is invasive and will cause unnecessary pain to AD patients, OCT has received widespread attention as a non-invasive technology.

[0005] OCT is an effective non-invasive optical imaging technology that uses reverse reflected light to provide micron resolution cross-sectional images of biological tissues. It uses the different reflectivity of different tissues in the eye to light (using 830nm near-infrared light) and uses a low-coherence optical interferometer to compare the reflected light wave with the reference light wave to measure the delay time and reflection intensity of the emitted light wave, analyze the structure of different tissues and their distances, calculate and process the image, and display the cross-sectional structure of the tissue in pseudo-color. The axial resolution can reach 10 microns, which has important application value in the diagnosis of macular diseases. OCT can be used to image the layered structure of the retina, and the full-layer retinal image can be segmented to quantify each layer, especially in the detection and imaging of living biological tissues. It has broad application prospects.

[0006] Optical coherence tomography is a non-invasive technology that can obtain cross-sectional images of retinal structures. Based on the principle of low-coherence interference of light, it obtains the backscattered light of the sample and reconstructs a two-dimensional tomographic or three-dimensional structural image of the sample by demodulating and processing the interference signal. It combines low-coherence interference technology, confocal microscopy technology, heterodyne detection technology, digital image processing and other technologies. Compared with other imaging technologies such as nuclear magnetic resonance and ultrasound imaging, it has the advantages of high resolution and low price, and has attractive application prospects in in vivo detection and imaging of biological tissues. Summary of the invention

[0007] The purpose of the present invention is to provide a method for evaluating cognitive dysfunction based on OCT imaging technology, so as to provide a method for predicting cognitive dysfunction that is non-invasive, causes little pain to the subject, is highly safe, and has good accuracy, thereby achieving early intervention in patients with cognitive dysfunction and delaying the onset of cognitive dysfunction.

[0008] To achieve the above object, the present invention provides a method for evaluating cognitive dysfunction based on OCT imaging technology, comprising the following steps:

[0009] S1. Perform a complete ophthalmological examination on the subject to determine whether the subject is suitable for the cognitive dysfunction prediction method based on OCT imaging technology;

[0010] S2. performing OCT image scanning on the fundus of the subject suitable for the cognitive dysfunction prediction method based on OCT imaging technology;

[0011] S3, performing OCT image analysis on the fundus OCT image of the subject obtained in S2 to obtain the final value of each analysis item;

[0012] S4. Compare the final values ​​of each item respectively. When the final value of at least one item is judged as suffering from cognitive dysfunction, the subject is judged to suffer from cognitive dysfunction, and the most serious result in each item is taken as the final judgment result.

[0013] Preferably, the subjects in S1 who suffer from diseases that cause turbidity of fundus medium are not suitable for the cognitive dysfunction prediction method based on OCT imaging technology, including those who suffer from glaucoma, macular degeneration and retinal vascular disease.

[0014] Preferably, to determine whether the subject suffers from the disease causing turbidity of the fundus medium, the test is performed under the conditions that the subject's corrected visual acuity is >0.5, the refractive error is between ±2 spherical diopters, and the intraocular pressure is less than 18 mmHg, and before the test, the subject's pupil is dilated with 1% compound tropicamide.

[0015] Preferably, the parts that need to be scanned by OCT images in S2 include: the retina in the macular area, the retinal nerve fiber layer in the macular area, the ganglion cell layer in the macular area, the retinal nerve fiber layer in the optic disc area, the retina in the optic disc area, and the ganglion cell layer in the optic disc area; the retinal nerve fiber layer in the macular area and the retinal nerve fiber layer in the optic disc area adopt the retinal nerve fiber layer thickness circle scanning mode; the scanning of the retina in the macular area, the retinal nerve fiber layer in the macular area, and the ganglion cell layer in the macular area is carried out by performing 6 consecutive 6mm radial line scans with the macula as the center.

[0016] Preferably, in S3, OCT image analysis is performed on the fundus OCT image of the subject, and the analyzed items include: retinal thickness in the macular area, retinal nerve fiber layer thickness in the macular area, ganglion cell layer thickness in the macular area, retinal nerve fiber layer thickness in the optic disc area, retinal thickness in the optic disc area, ganglion cell layer thickness in the optic disc area, optic disc area, optic cup area, area-to-cup ratio, horizontal cup-to-disc ratio, and vertical cup-to-disc ratio.

[0017] Preferably, when performing OCT image analysis on the fundus OCT image of the subject in S3, the retina in the macular area and the retina in the optic disc area are divided into the upper quadrant, the lower quadrant, the temporal quadrant and the nasal quadrant, and the final thickness value is the average value of each quadrant.

[0018] Preferably, when the retinal thickness of the macular area in S4 is greater than or equal to 250 μm, the subject has normal cognitive function, and when it is less than 250 μm, the subject has cognitive dysfunction;

[0019] When the thickness of the retinal nerve fiber layer in the macular area is greater than or equal to 35 μm, the subject has normal cognitive function; when it is less than 35 μm, the subject has cognitive dysfunction;

[0020] When the thickness of the ganglion cell layer in the macular area is greater than or equal to 65 μm, the subject has normal cognitive function; when it is less than 65 μm, the subject has cognitive dysfunction;

[0021] When the thickness of the retinal nerve fiber layer in the optic disc area is greater than or equal to 88 μm, the subject has normal cognitive function; when it is less than 88 μm, the subject has cognitive dysfunction;

[0022] When the retinal thickness of the optic disc area is greater than or equal to 260 μm, the subject has normal cognitive function; when it is less than 260 μm, the subject has cognitive dysfunction;

[0023] When the thickness of the ganglion cell layer in the optic disc area is greater than or equal to 40 μm, the subject has normal cognitive function; when it is less than 40 μm, the subject has cognitive dysfunction;

[0024] When the optic disc area is less than 2 μm, the subject has normal cognitive function; when it is greater than or equal to 2 μm, the subject has cognitive impairment;

[0025] When the optic cup area is less than 0.3 μm, the subject has normal cognitive function; when it is greater than or equal to 0.3 μm, the subject has cognitive impairment;

[0026] When the cup-to-disc ratio is less than 0.2 μm, the subject has normal cognitive function; when it is greater than or equal to 0.2 μm, the subject has cognitive impairment;

[0027] When the horizontal cup-to-disc ratio is less than 0.5 μm, the subject has normal cognitive function; when it is greater than or equal to 0.5 μm, the subject has cognitive impairment;

[0028] When the vertical cup-to-disc ratio is less than 0.4 μm, the subject has normal cognitive function; when it is greater than or equal to 0.4 μm, the subject has cognitive dysfunction.

[0029] Therefore, the present invention provides a method for evaluating cognitive dysfunction based on OCT imaging technology, and its specific technical effects are as follows:

[0030] (1) The method for predicting cognitive dysfunction based on OCT imaging technology provided by the present invention has high prediction accuracy, effectively reduces / avoids the phenomenon of missed diagnosis and unclear diagnosis, and has important practical value for the early detection of cognitive dysfunction;

[0031] (2) The method for predicting cognitive dysfunction based on OCT imaging technology provided by the present invention does not require lumbar puncture for the subject, is non-invasive, causes little pain to the subject, and is highly safe. It is helpful for popularizing the screening of cognitive dysfunction, identifying people at high risk of cognitive dysfunction, and thus achieving early intervention for patients with cognitive dysfunction and delaying the onset of cognitive dysfunction.

[0032] (3) The method for predicting cognitive dysfunction based on OCT imaging technology provided by the present invention is simple and easy to operate, and many of the examinations and measurements therein can be achieved by setting parameters for the instrument.

[0033] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0035] Figure 1 It is a flow chart of the cognitive dysfunction assessment method based on OCT imaging technology provided by the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0037] In order to make the purpose, technical scheme and advantages of the present application clearer, more thorough and complete, the technical scheme of the present invention is clearly and completely described below through the accompanying drawings and examples. The following detailed descriptions are all descriptions of the embodiments, and are intended to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs.

[0038] The instruments, equipment, reagents and materials used in the examples were all obtained through commercial channels.

[0039] Embodiment 1

[0040] A method for evaluating cognitive dysfunction based on OCT imaging technology, the process is as follows Figure 1 As shown, the specific steps include:

[0041] S1. Perform a complete ophthalmic examination on the subject to determine whether the subject is suitable for the method for predicting cognitive dysfunction based on OCT imaging technology provided by the present invention.

[0042] Obtain a complete ophthalmological examination report of the patient under the conditions of corrected visual acuity>0.5, refractive error between ±2 spherical diopters, and intraocular pressure (IOP) less than 18 mmHg, including visual function examination (assessment of best corrected visual acuity, eye movement), eyelid, eyelash, conjunctiva, pupil examination (pupil reflex, slit lamp biomicroscope observation), and use 1% compound tropicamide to dilate the pupil before fundus examination. To exclude patients with glaucoma and macular degeneration retinal vascular disease, glaucoma, macular degeneration retinal vascular disease, etc. will cause media turbidity, which will hinder eye and OCT examination. Therefore, patients with glaucoma and macular degeneration retinal vascular disease are not suitable for this prediction method. When using a non-contact tonometer to measure IOP, the average of 5 measurements is used as the intraocular pressure value.

[0043] S2. Performing OCT image scanning on the fundus of the subject suitable for the cognitive dysfunction prediction method based on OCT imaging technology provided by the present invention.

[0044] The areas where OCT images are scanned include: retina in the macular area, retinal nerve fiber layer in the macular area, ganglion cell layer in the macular area, retinal nerve fiber layer in the optic disc area, retina in the optic disc area, and ganglion cell layer in the optic disc area.

[0045] The retinal nerve fiber layer in the macular area and the retinal nerve fiber layer in the optic disc area were scanned using a retinal nerve fiber layer thickness circular scanning mode, which consisted of three circular scans with a radius of twice 3.4 mm centered on the ONH. The scanning of the retina in the macular area, the retinal nerve fiber layer in the macular area, and the ganglion cell layer in the macular area was performed with six consecutive 6 mm radial line scans centered on the macula.

[0046] S3. Analyze the fundus OCT image scanning results of subjects with non-glaucoma and macular degeneration retinal vascular disease, and the analysis items include: retinal thickness in the macular area, retinal nerve fiber layer thickness in the macular area, ganglion cell layer thickness in the macular area, retinal nerve fiber layer thickness in the optic disc area, retinal thickness in the optic disc area, ganglion cell layer thickness in the optic disc area, optic disc area, optic cup area, area-to-cup ratio, horizontal cup-to-disc ratio, and vertical cup-to-disc ratio.

[0047] During the analysis, the retina in the macular area and the optic disc area were divided into the superior quadrant, inferior quadrant, temporal quadrant, and nasal quadrant, and the final thickness value was the average value of each quadrant.

[0048] S4. Compare the final values ​​of each item separately:

[0049] When the retinal thickness in the macular area is greater than or equal to 250 μm, the subject has normal cognitive function; when it is less than 250 μm, the subject has cognitive dysfunction;

[0050] When the thickness of the retinal nerve fiber layer in the macular area is greater than or equal to 35 μm, the subject has normal cognitive function; when it is less than 35 μm, the subject has cognitive dysfunction;

[0051] When the thickness of the ganglion cell layer in the macular area is greater than or equal to 65 μm, the subject has normal cognitive function; when it is less than 65 μm, the subject has cognitive dysfunction;

[0052] When the thickness of the retinal nerve fiber layer in the optic disc area is greater than or equal to 88 μm, the subject has normal cognitive function; when it is less than 88 μm, the subject has cognitive dysfunction;

[0053] When the retinal thickness of the optic disc area is greater than or equal to 260 μm, the subject has normal cognitive function; when it is less than 260 μm, the subject has cognitive dysfunction;

[0054] When the thickness of the ganglion cell layer in the optic disc area is greater than or equal to 40 μm, the subject has normal cognitive function; when it is less than 40 μm, the subject has cognitive dysfunction;

[0055] When the optic disc area is less than 2 μm, the subject has normal cognitive function; when it is greater than or equal to 2 μm, the subject has cognitive impairment;

[0056] When the optic cup area is less than 0.3 μm, the subject has normal cognitive function; when it is greater than or equal to 0.3 μm, the subject has cognitive impairment;

[0057] When the cup-to-disc ratio is less than 0.2 μm, the subject has normal cognitive function; when it is greater than or equal to 0.2 μm, the subject has cognitive impairment;

[0058] When the horizontal cup-to-disc ratio is less than 0.5 μm, the subject has normal cognitive function; when it is greater than or equal to 0.5 μm, the subject has cognitive impairment;

[0059] When the vertical cup-to-disc ratio is less than 0.4 μm, the subject has normal cognitive function; when it is greater than or equal to 0.4 μm, the subject has cognitive dysfunction.

[0060] When the final value of at least one item is judged as suffering from cognitive dysfunction, the subject is judged to suffer from cognitive dysfunction, and the most serious result is taken as the final judgment result.

[0061] Embodiment 2

[0062] The prediction accuracy of the cognitive dysfunction prediction method based on OCT imaging technology provided by the present invention was examined.

[0063] The medical records of patients diagnosed with cognitive dysfunction obtained from the hospital were examined, and patients who did not suffer from glaucoma, macular degeneration, retinal vascular lesions, and other lesions that would cause fundus media turbidity were selected. Five patients with severe cognitive dysfunction who were willing to serve as volunteers were randomly selected for the following examinations and recorded as the cognitive dysfunction group. Five patients who were confirmed to have normal cognitive function obtained from the hospital were randomly selected for the following examinations and recorded as the normal cognitive group. Fundus OCT image scanning was performed, and the scanning areas included: retina in the macular area, retinal nerve fiber layer in the macular area, ganglion cell layer in the macular area, retinal nerve fiber layer in the optic disc area, retina in the optic disc area, and ganglion cell layer in the optic disc area.

[0064] The retinal nerve fiber layer in the macular area and the retinal nerve fiber layer in the optic disc area were scanned using a retinal nerve fiber layer thickness circular scanning mode, which consisted of three circular scans with a radius of twice 3.4 mm centered on the ONH. The scanning of the retina in the macular area, the retinal nerve fiber layer in the macular area, and the ganglion cell layer in the macular area was performed with six consecutive 6 mm radial line scans centered on the macula.

[0065] The fundus OCT image scanning results of the subjects with non-glaucoma and macular degeneration retinal vascular disease were analyzed, and the analysis items included: retinal thickness in the macular area, retinal nerve fiber layer thickness in the macular area, ganglion cell layer thickness in the macular area, retinal nerve fiber layer thickness in the optic disc area, retinal thickness in the optic disc area, ganglion cell layer thickness in the optic disc area, optic disc area, optic cup area, area cup-disc ratio, horizontal cup-disc ratio, and vertical cup-disc ratio. During the analysis, the retina in the macular area and the retina in the optic disc area were divided into the upper quadrant, the lower quadrant, the temporal quadrant, and the nasal quadrant, and the final thickness value was the average value of each quadrant.

[0066] Check the calculation results as shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] Note: The unit of data in the table is μm

[0071] As can be seen from Table 1, in the cognitive normal group, the average macular retinal thickness was greater than 250 μm, the macular retinal nerve fiber layer thickness was greater than 35 μm, the macular ganglion cell layer thickness was greater than 65 μm, the optic disc retinal nerve fiber layer thickness was greater than 88 μm, the optic disc retinal thickness was greater than 260 μm, the optic disc ganglion cell layer thickness was greater than 40 μm, the optic disc area was less than 2 μm, the optic cup area was less than 0.3 μm, the area cup-disc ratio was less than 0.2 μm, the horizontal cup-disc ratio was less than 0.5 μm, and the vertical cup-disc ratio was less than 0.4 μm, which met the judgment criteria of the cognitive dysfunction prediction method based on OCT imaging technology proposed in the present invention.

[0072] The average retinal nerve fiber layer thickness in the optic disc area of ​​the cognitive impairment group was less than 88 μm, the area cup-disc ratio was greater than 0.2 μm, the horizontal cup-disc ratio was greater than 0.5 μm, and the vertical cup-disc ratio was greater than 0.4 μm, which met the judgment criteria of the cognitive dysfunction prediction method based on OCT imaging technology proposed in the present invention.

[0073] Therefore, the cognitive dysfunction prediction method based on OCT imaging technology provided by the present invention has high prediction accuracy, effectively reduces / avoids missed diagnosis and unclear diagnosis, and has important practical value for the early detection of cognitive dysfunction; it does not require lumbar puncture for the subject, is non-invasive, causes less pain to the subject, and is highly safe, which is conducive to the popularization of cognitive dysfunction screening, determines the high-risk population for cognitive dysfunction, and then achieves early intervention for patients with cognitive dysfunction and delays the onset of cognitive dysfunction; it is simple and easy to operate, and many of the examinations and measurements can be achieved by setting parameters for instruments and equipment.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for evaluating cognitive dysfunction based on OCT imaging technology, characterized in that: The following steps are involved: S1. Perform a complete ophthalmological examination on the subject to determine whether the subject is suitable for the cognitive dysfunction prediction method based on OCT imaging technology; S2. performing OCT image scanning on the fundus of the subject suitable for the cognitive dysfunction prediction method based on OCT imaging technology; S3, performing OCT image analysis on the fundus OCT image of the subject obtained in S2 to obtain the final value of each analysis item; S4. Compare the final values ​​of each item respectively. When the final value of at least one item is judged as suffering from cognitive dysfunction, the subject is judged to suffer from cognitive dysfunction, and the most serious result in each item is taken as the final judgment result.

2. The method for evaluating cognitive dysfunction based on OCT imaging technology according to claim 1, characterized in that: The subjects in S1 who suffer from diseases that cause turbidity of the fundus medium are not suitable for the cognitive dysfunction prediction method based on OCT imaging technology, including those who suffer from glaucoma and macular degeneration retinal vascular disease.

3. The method for evaluating cognitive dysfunction based on OCT imaging technology according to claim 2, characterized in that: To determine whether the subject suffers from the disease causing fundus medium turbidity, the test is conducted under the conditions that the subject's corrected visual acuity is >0.5, the refractive error is between ±2 spherical diopters, and the intraocular pressure is less than 18 mmHg. Before the test, the subject is first dilated with 1% compound tropicamide.

4. The method for evaluating cognitive dysfunction based on OCT imaging technology according to claim 1, characterized in that: The parts that need to be scanned by OCT images in S2 include: the retina in the macular area, the retinal nerve fiber layer in the macular area, the ganglion cell layer in the macular area, the retinal nerve fiber layer in the optic disc area, the retina in the optic disc area, and the ganglion cell layer in the optic disc area; the retinal nerve fiber layer in the macular area and the retinal nerve fiber layer in the optic disc area adopt the retinal nerve fiber layer thickness circle scanning mode; the scanning of the retina in the macular area, the retinal nerve fiber layer in the macular area, and the ganglion cell layer in the macular area is carried out by performing 6 consecutive 6mm radial line scans with the macula as the center.

5. The method for evaluating cognitive dysfunction based on OCT imaging technology according to claim 1, characterized in that: In the S3, OCT image analysis is performed on the fundus OCT image of the subject, and the analyzed items include: retinal thickness in the macular area, retinal nerve fiber layer thickness in the macular area, ganglion cell layer thickness in the macular area, retinal nerve fiber layer thickness in the optic disc area, retinal thickness in the optic disc area, ganglion cell layer thickness in the optic disc area, optic disc area, optic cup area, area-to-cup ratio, horizontal cup-to-disc ratio, and vertical cup-to-disc ratio.

6. The method for evaluating cognitive dysfunction based on OCT imaging technology according to claim 5, characterized in that: When performing OCT image analysis on the fundus OCT image of the subject in S3, the retina in the macular area and the retina in the optic disc area are divided into the upper quadrant, the lower quadrant, the temporal quadrant and the nasal quadrant, and the final thickness value is the average value of each quadrant.

7. The method for evaluating cognitive dysfunction based on OCT imaging technology according to claim 1, characterized in that: When the retinal thickness of the macular area in S4 is greater than or equal to 250 μm, the subject has normal cognitive function; when it is less than 250 μm, the subject has cognitive dysfunction; When the thickness of the retinal nerve fiber layer in the macular area is greater than or equal to 35 μm, the subject has normal cognitive function; when it is less than 35 μm, the subject has cognitive dysfunction; When the thickness of the ganglion cell layer in the macular area is greater than or equal to 65 μm, the subject has normal cognitive function; when it is less than 65 μm, the subject has cognitive dysfunction; When the thickness of the retinal nerve fiber layer in the optic disc area is greater than or equal to 88 μm, the subject has normal cognitive function; when it is less than 88 μm, the subject has cognitive dysfunction; When the retinal thickness of the optic disc area is greater than or equal to 260 μm, the subject has normal cognitive function; when it is less than 260 μm, the subject has cognitive dysfunction; When the thickness of the ganglion cell layer in the optic disc area is greater than or equal to 40 μm, the subject has normal cognitive function; when it is less than 40 μm, the subject has cognitive dysfunction; When the optic disc area is less than 2 μm, the subject has normal cognitive function; when it is greater than or equal to 2 μm, the subject has cognitive impairment; When the optic cup area is less than 0.3 μm, the subject has normal cognitive function; when it is greater than or equal to 0.3 μm, the subject has cognitive impairment; When the cup-to-disc ratio is less than 0.2 μm, the subject has normal cognitive function; when it is greater than or equal to 0.2 μm, the subject has cognitive impairment; When the horizontal cup-to-disc ratio is less than 0.5 μm, the subject has normal cognitive function; when it is greater than or equal to 0.5 μm, the subject has cognitive impairment; When the vertical cup-to-disc ratio is less than 0.4 μm, the subject has normal cognitive function; when it is greater than or equal to 0.4 μm, the subject has cognitive dysfunction.

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