A scanning method and system for a full eye OCT

Abstract

The application provides a scanning method and system of full-eye OCT, and relates to the technical field of eye scanning.The method comprises the following steps: S1, triggering a reference arm of a preset optical path by a synchronous control circuit; S2, applying a voltage to a liquid lens by the synchronous control circuit to control the liquid lens to adjust to a preset width of light focusing; S3, splitting incident light into a first light path and a second light path by a fiber coupler, and obtaining first reflected light and second reflected light through a preset light reflection process; S4, reflecting the first reflected light and the second reflected light along the original light path, and then entering a spectrometer after being synthesized and decomposed at the fiber coupler; and S5, detecting the output light beam by a photoelectric detector after the output light beam is output by the spectrometer, converting the measured analog signal into a digital signal, and obtaining image information after processing. The method can effectively shorten the time for switching between the anterior segment scanning and the posterior segment scanning of OCT.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of eye scanning, in particular to a full eye OCT scanning method and system. BACKGROUND

[0002] OCT (Optical Coherence Tomography) is a new non-contact non-invasive optical imaging diagnostic technology developed in the early 1990s. Its principle is similar to that of ultrasonic waves, except that light is used instead of sound waves to produce images. OCT is commonly used in the examination and diagnosis of ophthalmic diseases. Compared with other medical imaging equipment, OCT has the advantages of simple operation, easy to master, no radiation, non-contact, high sensitivity, high resolution, convenience, repeatability, and good at capturing various small lesions. Eye OCT examination is mainly used to examine various abnormalities and lesions of the eye, including retinal detachment, retinal arteriovenous obstruction, macular cystic edema, glaucoma, and can also be used to diagnose retinal hemorrhage, retinal vascular lesions and other abnormalities. OCT examination covers the anterior segment to the posterior segment of the eye, basically covering all tissues of the eye.

[0003] Full eye OCT scanning is composed of anterior segment OCT scanning and posterior segment OCT scanning. The anterior segment of the eye is located on the surface, from the cornea to the angle, iris, part of the lens, and the anterior segment OCT can display the structure of the anterior segment, such as the root of the iris, the recess of the angle, the superficial surface of the ciliary body, the scleral spur, the trabecular meshwork, Schlemm's canal, etc. The corneal thickness and related parameters of the anterior chamber can be measured, with high accuracy and repeatability. The retina, optic nerve and vitreous body belong to the posterior segment, and the posterior segment OCT is more commonly used in clinical practice, which is simply called OCT. It has important diagnostic value for various diseases of the fundus, such as edema, rhexis, anterior membrane, splitting, neuroepithelial and pigment epithelial detachment, vitreoretinal traction, CNV, etc. It can also be used for quantitative measurement of nerve fiber layer thickness in glaucoma and follow-up of glaucoma. With the development of instruments, the resolution and scanning depth are continuously improved, and the posterior segment OCT can also clearly display the fine light bands of retinal photoreceptors and measure the thickness of choroid.

[0004] The current full eye OCT scanning needs to first perform anterior segment OCT scanning, and then switch the reference arm optical path by a motor-driven mirror and replace different specifications of lenses to focus the incident light on the fovea of the fundus, which is a two-step operation. Only in this way can the anterior and posterior segment scanning switching be realized, and the full eye scanning be completed. However, this process takes a long time, and the patient may be tired due to long-time eye opening during this period, resulting in blinking or eye movement, which affects the examination results. SUMMARY

[0005] The present application solves the problem of how to effectively shorten the time of OCT pre and post scanning switching.

[0006] To solve the above problems, the present application provides a scanning method of full eye OCT, comprising the steps of:

[0007] S1: triggering the light switch to select the reference arm of the preset optical path through the synchronous control circuit;

[0008] S2: applying voltage to the liquid lens through the synchronous control circuit to control the liquid lens to adjust to the preset width of light focusing;

[0009] S3: the incident light is split into first and second optical paths through the optical fiber coupler, and first and second reflected lights are obtained after passing through the preset light reflection process;

[0010] S4: the first and second reflected lights are reflected along the original optical path, and after being synthesized and decomposed at the optical fiber coupler, they enter the spectrometer;

[0011] S5: after the output light beam of the spectrometer, the output light beam is detected by the photoelectric detector, and the measured analog signal is converted into a digital signal, and the image information is obtained after processing.

[0012] In the above method, the light switch is triggered by the synchronous control circuit to select the reference arm of the preset optical path; the liquid lens is synchronously pressurized to adjust to the width required for light focusing; and the spectrometer is also controlled to work. The incident light is split into two optical paths by the optical fiber coupler: one path passes through the reference arm selected by the light switch and is reflected by the reference mirror to obtain the first reflected light; the other path passes through the ordinary lens to become parallel light, and then falls on the estimated focal point of the eyeball through the pressurized liquid lens, and then is reflected by the eyeball to obtain the second reflected light. The first and second reflected lights are reflected along the original optical path, and after being synthesized and decomposed at the optical fiber coupler, they enter the spectrometer.

[0013] Further, the preset light reflection process in step S3 comprises:

[0014] S31: selecting the reference arm of the preset optical path for the first optical path through the light switch, and obtaining the first reflected light through the reflection of the reference mirror;

[0015] S32: converting the second optical path into parallel light through the lens, and falling on the focal point of the target eyeball through the voltage-applied liquid lens, and obtaining the second reflected light through the reflection of the eyeball.

[0016] Further, it further comprises the steps of:

[0017] S6: the x-y scanning galvanometer is used for two-dimensionally scanning the eyeball, measuring the anterior ocular segment distance x from the corneal vertex and the posterior ocular segment distance z of the fovea of the fundus, and measuring the axial length by x+y+z in the full eye scanning by adopting a default value y for the intermediate position except the anterior and posterior ocular segments.

[0018] Further, the wavelength of the incident light is 840 nm, the bandwidth length is 50 nm, and the output power is 10 mW.

[0019] A scanning system of the full eye OCT comprises:

[0020] The control unit is used for triggering the reference arm of the preset optical path by the synchronous control circuit through the light switch;

[0021] The adjusting unit is used for adjusting the preset width of the liquid lens to the light focusing by applying the voltage to the liquid lens through the synchronous control circuit;

[0022] The fiber coupler is used for splitting the incident light into the first optical path and the second optical path when the incident light passes, obtaining the first reflected light and the second reflected light through the preset light reflection process, and reflecting the first reflected light and the second reflected light along the original optical path to enter the spectrometer after being synthesized and decomposed through the fiber coupler;

[0023] The spectrometer is used for detecting the output light beam through the photoelectric detector after the output light beam, converting the measured analog signal into a digital signal, and obtaining the image information through processing.

[0024] Further, the preset light reflection process comprises:

[0025] The light switch is used for selecting the reference arm of the preset optical path through the switching for the first optical path, reflecting through the reference mirror to obtain the first reflected light;

[0026] The lens is used for converting the second optical path into parallel light, falling on the eyeball focal point of the target through the liquid lens to which the voltage has been applied, reflecting through the eyeball to obtain the second reflected light.

[0027] Further, the scanning system further comprises:

[0028] The scanning galvanometer is used for two-dimensionally scanning the eyeball, measuring the anterior ocular segment distance x from the corneal vertex and the posterior ocular segment distance z of the fovea of the fundus, and measuring the axial length by x+y+z in the full eye scanning by adopting a default value y for the intermediate position except the anterior and posterior ocular segments.

[0029] The technical scheme has the following beneficial effects:

[0030] The present application can trigger the light switch to select the reference arm with different optical path by the synchronous control circuit; the liquid lens is pressurized synchronously to adjust to the width required by the light focusing; the spectrometer is also controlled to work, the light switch switches the reference arm with different optical path, and the liquid lens is pressurized to generate shrinkage to control the focus position of the incident light on the eyeball, the fast switching of the anterior and posterior segment scanning in a short time is realized, and the time of the whole eye scanning is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The schematic diagram of the OCT scanning analog optical path in the full eye OCT scanning method provided by the embodiment one of the present application is shown in the figure.

[0032] Figure 2 The flow chart of the full eye OCT scanning method provided by the embodiment one of the present application is shown in the figure. Figure 1

[0033] The schematic diagram of the eye axis measurement in the full eye OCT scanning method provided by the embodiment one of the present application is shown in the figure. Figure 3 Figure 2 The structure of the full eye OCT scanning system provided by the embodiment two of the present application is shown in the figure.

[0034] Figure 4 The structure of the full eye OCT scanning system provided by the embodiment two of the present application is shown in the figure.

[0035] Figure 5 Figure 1 The schematic diagram of the synchronous control circuit of the full eye OCT scanning system provided by the embodiment two of the present application is shown in the figure. DETAILED DESCRIPTION

[0036] Figure 6 In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. Figure 2 The specific embodiments of the present application are described below with reference to the accompanying drawings, and the technical solutions of the present application are further described, but the present application is not limited to these embodiments.

[0037] Figure 7 Embodiment one The present embodiment provides a full eye OCT scanning method, as shown in the figures, the method comprises the following steps:

[0038] The specific embodiments of the present application are described below with reference to the accompanying drawings, and the technical solutions of the present application are further described, but the present application is not limited to these embodiments.

[0039] Embodiment one

[0040] The present embodiment provides a full eye OCT scanning method, as shown in the figures, the method comprises the following steps:

[0041] Figure 1 Figure 2 The specific embodiments of the present application are described below with reference to the accompanying drawings, and the technical solutions of the present application are further described, but the present application is not limited to these embodiments.

[0042] ​​​S1: Triggering the light switch to select the reference arm of the preset optical path by the synchronous control circuit;

[0043] S2: Applying voltage to the liquid lens by the synchronous control circuit to control the liquid lens to adjust to the preset width of light focusing;

[0044] S3: The incident light is split into first and second light paths by the optical fiber coupler, and first and second reflected lights are obtained after passing through the preset light reflection process;

[0045] S4: The first and second reflected lights are reflected along the original light path, and after being synthesized and decomposed at the optical fiber coupler, they enter the spectrometer;

[0046] S5: After the output light beam of the spectrometer, the output light beam is detected by the photoelectric detector, and the measured analog signal is converted into a digital signal, and the image information is obtained after processing.

[0047] Specifically, the reference arm of the preset optical path includes two reference arms of different optical paths, and the synchronous control circuit triggers the light switch to select the reference arm of the preset different optical path; the liquid lens is pressurized synchronously to adjust the liquid lens to the width required for light focusing; and the spectrometer is also controlled to work. The incident light is split into two light paths by the optical fiber coupler: the first light path is reflected by the reference mirror after passing through the reference arm selected by the light switch, and the second light path is first converted into parallel light by a common lens, and then falls on the estimated focal point of the eyeball after passing through the pressurized liquid lens, and then the second reflected light is obtained after being reflected by the eyeball.

[0048] Specifically, the first and second reflected lights are reflected along the original light path, and after being synthesized and decomposed at the optical fiber coupler, they enter the spectrometer, and after the output light beam of the spectrometer, the output light beam is detected by the photoelectric detector, and the measured analog signal is converted into a digital signal, and the image information is obtained after processing by the computer. Light source properties: wavelength 840nm, bandwidth length ~50nm, output power ~10mW, and scanning speed of 40-120kHz (40000-120000 A-lines / s) can be provided.

[0049] Specifically, an x-y scanning galvanometer with a diameter of 15mm is configured to quickly realize two-dimensional scanning of the sample to be measured. A part of the light source signal is coupled into a Mach-Zehnder interferometer to calibrate the signal generated by the asymmetry of the sample arm and the reference arm. Lateral resolution: ~15.0um, axial resolution: ~5um. System sensitivity of >120dB is achieved. Imaging range: 15mm x 15mm; imaging depth: ~4mm. Real-time acquisition, processing and storage rate: 40-215fps (frames / second). Anterior-posterior segment switching frequency: 100Hz.

[0050] Specifically, the preset width is represented as: a suitable width required for the liquid lens to adjust to the best focus point of the light when the liquid lens is pressurized synchronously.

[0051] Referring to Figure 3 The preset light reflection process in step S3 includes:

[0052] S31: Selecting a reference arm of a preset optical path for the first light path through the optical switch, and obtaining the first reflected light through reflection of the reference arm mirror;

[0053] S32: Converting the second light path into parallel light through the lens, falling on the eyeball focal point of the target through the liquid lens with the applied voltage, and obtaining the second reflected light through the eyeball reflection.

[0054] Referring to Figure 3 and Figure 4 The method further includes the following steps:

[0055] S6: Two-dimensional scanning of the eyeball is performed through the x-y scanning galvanometer, the anterior segment distance x from the corneal vertex and the posterior segment distance z to the fovea of the fundus are measured, the default value y is used for the intermediate position except the anterior and posterior segments, and the axial length is measured through x+y+z in the full eye scanning.

[0056] Specifically, after the measurement is completed, the difference between the axial length of the patient's eye and the normal axial length can be used to determine whether the eyeball is diseased.

[0057] The wavelength of the incident light is 840 nm, the bandwidth length is 50 nm, and the output power is 10 mW.

[0058] Specifically, during the scanning, the anterior and posterior segments can be focused, and the light return efficiency is high. When the full eye scanning is performed by using the above method, no matter the scanning position is the anterior segment or the posterior segment of the eye, the liquid lens can control the light position, so that the light is focused on the best focus point, the light return efficiency of the eye is higher, and the imaging effect is better.

[0059] The method triggers the optical switch to select the reference arm with the set different optical path through the synchronous control circuit, synchronously pressurizes the liquid lens to adjust the liquid lens to the width required for the light focusing, and controls the spectrometer to work at the same time. The optical switch switches the reference arm with different optical paths, and the liquid lens is pressurized to generate contraction to control the incident light at the focal point position of the eyeball. The fast switching of the anterior and posterior segment scanning is realized in a short time, and the time of the full eye scanning is effectively reduced.

[0060] Embodiment Two

[0061] The embodiment provides a scanning system for full eye OCT, as shown in Figure 5 and Figure 6 The system includes:

[0062] The control unit is configured to select the reference arm of the preset optical path by triggering the optical switch through the synchronous control circuit;

[0063] The adjustment unit is configured to apply a voltage to the liquid lens through the synchronous control circuit to adjust the preset width of the liquid lens to the light focusing;

[0064] The optical fiber coupler is configured to split the incident light into a first optical path and a second optical path when the incident light passes through, obtain first reflected light and second reflected light through the preset light reflection process, and reflect the first reflected light and the second reflected light along the original optical path to enter the spectrometer after being synthesized and decomposed by the optical fiber coupler;

[0065] The spectrometer is configured to detect the output light beam through the photodetector after the output light beam, convert the measured analog signal into a digital signal, and obtain image information after processing.

[0066] Referring to Figure 6 , the preset light reflection process comprises:

[0067] The optical switch is configured to select the reference arm of the preset optical path for the first optical path, reflect through the reference arm mirror, and obtain the first reflected light;

[0068] The lens is configured to convert the second optical path into parallel light, pass through the liquid lens to which the voltage has been applied, fall on the eyeball focal point of the target, reflect through the eyeball, and obtain the second reflected light.

[0069] Further comprising:

[0070] The scanning galvanometer is configured to perform two-dimensional scanning on the eyeball, measure the anterior segment distance x from the corneal vertex and the posterior segment distance z of the fovea of the fundus, and measure the axial length by x+y+z when full eye scanning is performed by using a default value y for the intermediate position other than the anterior and posterior segments.

[0071] Referring to Figure 7 , the principle of applying a voltage to the liquid lens through the synchronous control circuit to adjust the preset width of the liquid lens to the light focusing is as follows: the processor controls the spectrometer through the first signal, controls two switching circuits connected with the optical switch driving circuit and the liquid lens driving circuit through the second signal, and the switching circuit connected with the liquid lens driving circuit is further connected with the processor through the anterior segment focal length setting and the posterior segment focal length setting. The processor is connected with the anterior segment optical path through the stepping motor driving circuit, and the posterior segment optical path is connected with the optical switch driving circuit through the optical switch. The synchronous control circuit is used to realize the switching of the fast scanning.

[0072] The system triggers the light switch to select the reference arm with different optical path through the synchronous control circuit; the liquid lens is pressurized synchronously to adjust to the width required by the light focusing; meanwhile, the spectrometer is controlled to work, the light switch switches the reference arm with different optical path, and the liquid lens is pressurized to generate contraction to control the focal point position of the incident light on the eyeball, the quick switching of the anterior and posterior segment scanning is realized in a short time, and the time of the whole eye scanning is effectively reduced.

[0073] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications shall fall within the protection scope of the present disclosure.

Claims

1. A scanning method of a full eye OCT, characterized by, The method comprises the steps of: S1: triggering a light switch to select a reference arm of a preset optical path through a synchronous control circuit; S2: applying a voltage to the liquid lens through the synchronous control circuit to control the liquid lens to adjust to a preset width of light focusing; S3: splitting the incident light into a first light path and a second light path through a fiber coupler, and obtaining first reflected light and second reflected light through a preset light reflection process; S4: reflecting the first reflected light and the second reflected light along the original light path, and entering the spectrometer after synthesis and decomposition at the fiber coupler; S5: detecting the output light beam through a photodetector after the output light beam of the spectrometer, converting the measured analog signal into a digital signal, and obtaining image information through processing; The preset light reflection process in step S3 comprises: S31: selecting a reference arm of a preset optical path for the first light path through a light switch, and obtaining first reflected light through reflection of a reference arm mirror; S32: converting the second light path into parallel light through a lens, falling on the eyeball focal point of the target through the liquid lens with the applied voltage, and obtaining second reflected light through eyeball reflection.

2. The scanning method of the full eye OCT according to claim 1, wherein, The method further comprises the step of: S6: performing two-dimensional scanning on the eyeball through an x-y scanning galvanometer, measuring the anterior segment distance x from the corneal vertex and the posterior segment distance z of the fovea of the fundus, adopting a default value y for the intermediate position except the anterior and posterior segments, and measuring the axial length through x+y+z in full eye scanning.

3. The scanning method of the full eye OCT according to claim 1, wherein, The wavelength of the incident light is 840 nm, the bandwidth length is 50 nm, and the output power is 10 mW.

4. A scanning system for a full eye OCT, characterized in that The method comprises: a control unit for triggering a light switch to select a reference arm of a preset optical path through a synchronous control circuit; an adjustment unit for applying a voltage to the liquid lens through the synchronous control circuit to adjust the liquid lens to a preset width of light focusing; a fiber coupler for splitting the incident light into a first light path and a second light path when the incident light passes through, obtaining first reflected light and second reflected light through a preset light reflection process, and reflecting the first reflected light and the second reflected light along the original light path, and entering the spectrometer after synthesis and decomposition at the fiber coupler; a spectrometer for detecting the output light beam through a photodetector after the output light beam of the spectrometer, converting the measured analog signal into a digital signal, and obtaining image information through processing; The preset light reflection process comprises: a light switch for selecting a reference arm of a preset optical path for the first light path through switching, and obtaining first reflected light through reflection of a reference arm mirror; a lens for converting the second light path into parallel light, falling on the eyeball focal point of the target through the liquid lens with the applied voltage, and obtaining second reflected light through eyeball reflection.

5. The scanning system of a full eye OCT according to claim 4, wherein, The method further comprises: a scanning galvanometer for performing two-dimensional scanning on the eyeball, measuring the anterior segment distance x from the corneal vertex and the posterior segment distance z of the fovea of the fundus, adopting a default value y for the intermediate position except the anterior and posterior segments, and measuring the axial length through x+y+z in full eye scanning.

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