CN113509142B

CN113509142B - Large-vision retina examination device

Info

Publication number: CN113509142B
Application number: CN202110630800.1A
Authority: CN
Inventors: 齐岳; 王熙; 赵鹏; 张锟; 王雪乔
Original assignee: Tianjin Suowei Electronic Technology Co ltd
Current assignee: Tianjin Suowei Electronic Technology Co ltd
Priority date: 2021-06-07
Filing date: 2021-06-07
Publication date: 2023-06-02
Anticipated expiration: 2041-06-07
Also published as: CN113509142A

Abstract

The invention relates to a large-vision retina examination device, which is characterized in that: the probe consists of a probe and an interferometer, wherein the interferometer is connected with a sample arm light path in the probe through an optical fiber tail fiber in the interferometer; the probe is used for carrying out color imaging and fluorescence contrast imaging on fundus and is also used as a sample arm light path for optical coherence tomography; the interferometer is used for optical coherence tomography of the fundus retina. The device can display the retina tomographic image while carrying out real-time color imaging on the fundus retina, and can also carry out fluorescence contrast imaging. The photographed image can be used for the comprehensive screening of fundus diseases, and is particularly suitable for early diagnosis and postoperative review of infant fundus retinopathy.

Description

Large-vision retina examination device

Technical Field

The invention belongs to the technical field of ophthalmic images, and relates to a large-vision fundus examination device which uses a white light LED and a near infrared broadband laser as illumination light sources and images through an optical lens, a camera and a spectrometer, in particular to a large-vision retina examination device.

Background

Retinal imaging techniques have been widely used in the field of ocular fundus disease detection. Medical science indicates that both ophthalmic diseases and systemic diseases of the body produce lesions in the fundus retina at an early stage of onset. The method can accurately and timely detect the retinopathy, can play a significant role in early diagnosis of diseases, and can also provide a good technical platform for pathology research of serious diseases. In clinic, instrument performance varies depending on the population of subjects and examination needs, for example, a large-field fundus imaging apparatus has advantages in evaluation of pathological features in peripheral regions of the retina. Also for example, tomographic imaging apparatus have advantages in terms of morphological analysis of the retina.

The most common fundus disease diagnosis device is a fundus camera, the imaging field of view of the fundus camera is generally not more than 50 degrees, and pathological feature analysis of the peripheral area of the retina cannot be completed, which causes a bottleneck for diagnosis of many diseases. For example, clinical early screening for retinopathy of prematurity (ROP) requires an imaging field of view of 120 degrees or more, which can be cured by laser surgery early in the onset, but overdosed to cause lifelong blindness.

Patent US5822036 discloses a handheld large field fundus imaging apparatus. The invention adopts a halogen lamp light source and adopts a plurality of optical fibers to arrange an illumination light ring which is arranged behind the edge of the contact lens to illuminate the eye bottom, and the illumination view field can be improved to more than 120 degrees. The invention also provides an annular prism between the optical fiber and the contact lens for controlling the illumination uniformity of the fundus. The method is high in design difficulty and complex in manufacturing process. Most importantly, the invention does not provide a tomographic image of the retina.

Patent US20090268020 discloses a hand-held large-field fundus tomographic imaging apparatus. The invention realizes the tomography of retina by using the weak optical coherence technology. An imaging field of view of up to 140 degrees may be provided. But the invention cannot provide a color image of the fundus in real time.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a large-vision retina examination device which can display a retina tomogram while carrying out real-time color imaging on the fundus retina and can also carry out fluorescence contrast imaging. The photographed image can be used for the comprehensive screening of fundus diseases, and is particularly suitable for early diagnosis and postoperative review of infant fundus retinopathy.

The invention solves the technical problems by adopting the following technical scheme:

the large-field retina inspection device consists of a probe and an interferometer, wherein the interferometer is connected with a sample arm light path in the probe through an optical fiber tail fiber in the interferometer;

the probe is used for carrying out color imaging and fluorescence contrast imaging on fundus and is also used as a sample arm light path for optical coherence tomography;

the interferometer is used for optical coherence tomography of the fundus retina.

Moreover, the length of the probe is not more than 250mm, and the weight is not more than 3kg.

The probe consists of an illumination module, a fundus imaging light path and a sample arm light path,

the illumination module consists of LED light sources, light homogenizing sheets and annular condensing lenses, wherein a plurality of LED light sources are distributed in a circular shape, the annular light homogenizing sheets are arranged in front of the formed circular ring, and the annular condensing lenses are arranged in front of the light homogenizing sheets.

When the LED light source emits light, the light homogenizing sheet can be regarded as an annular luminous body with uniform brightness in all directions. An annular condensing lens is arranged in front of the light homogenizing sheet, and light rays can pass through the contact lens of the ocular lens group and are projected on the surface of the human eye crystal to form a light ring. These rays continue to propagate forward and will spread out at the fundus to form a uniform illumination.

The fundus imaging light path consists of an ocular lens group, an imaging objective lens, a dichroic mirror, a low-pass filter, a fluorescent filter and an imaging camera, wherein light rays emitted by the illumination module are collected by the ocular lens group after being reflected by the fundus, an intermediate image plane R is formed behind the light rays, the imaging objective lens can perform secondary imaging on the intermediate image plane, and a final fundus image R' is formed on the imaging camera through the dichroic mirror and the low-pass filter or the fluorescent filter.

The sample arm light route is composed of an ocular lens group, an imaging objective lens, a dichroic mirror, a high-pass filter, a scanning objective lens, a scanning galvanometer and a first collimating mirror, wherein the ocular lens group, the imaging objective lens and the dichroic mirror are shared with a fundus imaging light path,

after the light emitted by the optical fiber tail fiber of the interferometer is bent into parallel light by the first collimating mirror, the parallel light is projected onto the scanning objective lens by the scanning galvanometer, the scanning objective lens converges the light on the rear focal plane of the scanning objective lens to form a light spot, the position of the light spot on the focal plane changes along with the change of the reflection angle of the scanning galvanometer to form a scanning image plane R ', the light spot at any position in the R ', through the high-pass filter, the dichroic mirror and the imaging objective lens, forms another equivalent light spot at the fundus of the human eye, the position of the equivalent light spot also changes along with the change of the position of the light spot in the R ', the fundus can reflect the equivalent light spot, and the light returns to the optical fiber tail fiber through the optical path of the sample arm to enter the interferometer.

The LED light source is a patch type LED, and is composed of white light LEDs and blue light LEDs which are arranged at intervals. The white light LED is a color imaging light source, the color temperature range is 4000K-5500K, and the color rendering index is not lower than 90%; the blue light LED is a fluorescence contrast light source, and the central wavelength range is 460 nm-490 nm. The number of each LED is not less than 6, and the light emitting angle is not less than 65 degrees.

The light homogenizing sheet is an acrylic plate or frosted glass with frosted surface, the surface roughness is not lower than 1000 meshes, and the light transmittance is not lower than 70%.

The annular condenser is an optical lens, one surface is a plane, the radius of curvature of the other surface is 2-10 mm, and the material is specifically determined by the refractive index of the material, and can be optical glass or optical resin.

The ocular lens group is composed of a contact lens, a conical lens and an ocular objective lens, and is used for collecting light reflected by eyeground to form an intermediate image surface R with better quality and low distortion.

The contact lens is an optical lens, and is required to be contacted with the cornea of a human eye when in work, and the curvature radius of the contact lens is similar to that of the cornea of the human eye.

The conical lens is a conical optical lens, the material of the conical lens is different from that of the contact lens, the conical lens and the contact lens form a cemented lens for eliminating chromatic aberration of a part of human eyes, and the illumination module is arranged on the outer ring of the conical lens.

The objective lens is a 1-group optical lens, and is used for eliminating aberration of human eyes, wherein the aberration mainly comprises spherical aberration, coma aberration, chromatic aberration and distortion.

And the imaging objective lens is 1 group of optical lenses, the focal length range is 10 mm-100 mm, and the imaging objective lens at least comprises 1 glued lens. The imaging objective lens moves back and forth along an imaging optical axis and is used for compensating individual difference of diopter of human eyes, so that an imaging image plane R' just falls on an imaging camera to form a clear fundus retina image. Furthermore, the imaging objective lens has image space telecentricity.

The dichroic mirror is an optical lens with a working angle of 45 degrees, and has the function of reflecting visible light and transmitting near infrared light at the same time, so that the visible light and the near infrared light propagate in mutually perpendicular directions after passing through the lens, and the purpose of separation is achieved.

The low-pass filter is an optical filter, the working angle is 0 degrees, and the low-pass filter is used for transmitting visible light and simultaneously cutting off near infrared light so as to prevent the near infrared light from entering an imaging camera to interfere an image.

The fluorescent filter is an optical filter, the working angle is 0 degrees, and the fluorescent filter is used for transmitting green fluorescence excited by blue light to irradiate fluorescein and cutting off light of other wave bands. A high contrast fluoroscopic image is formed.

The imaging camera is a CCD or CMOS camera, the photosensitive area is not more than 1 inch, the resolution is not less than 30 ten thousand pixels, and the imaging camera is positioned on an image plane R' of a fundus imaging light path to form an image.

Moreover, the low-pass filter and the fluorescent filter are switched for use, and only one of the low-pass filter and the fluorescent filter can be arranged in the fundus imaging optical path at a time. When the fundus is subjected to color imaging, a low-pass filter is used; and a fluorescence filter is used for fluorescence imaging of the fundus.

And the first collimating lens is an optical lens, the focal length range is 5 mm-25 mm, and the numerical aperture is not more than 0.5.

The scanning galvanometer is a scanning reflector, the reflection angle can be changed periodically, the scanning frequency is not lower than 100Hz, and the scanning angle is not more than +/-20 degrees.

The scanning objective lens is 1 group of optical lenses, and the focal length range is 20 mm-100 mm. But also the scanning objective has image-side telecentricity and low distortion characteristics.

The high-pass filter is an optical filter, the working angle is 0 degrees, and the high-pass filter is used for transmitting near infrared light and simultaneously cutting off visible light so as to prevent interference caused by entrance of visible light into the interferometer due to fundus reflection.

The interferometer consists of a weak coherent light source, a 2x2 optical fiber coupler, a polarization controller, an optical fiber tail fiber, a reference arm light path and a spectrometer, and is used for carrying out optical coherence tomography on the fundus retina;

the optical weak coherent light source is a super-radiation light-emitting diode, the central wavelength range of the optical weak coherent light source is 780-1100 nm, and the bandwidth is not narrower than 40nm;

the 2x2 optical fiber coupler is an optical fiber device and is provided with 4 tail fibers which are respectively connected into a weak coherent light source, a sample arm light path, a reference arm light path and a spectrometer; the interferometer has the functions that light rays emitted by the weak coherent light source can be respectively guided into a sample arm light path and a reference arm light path according to a set proportion, return light of the two light paths is collected to form interference signals, and then the interference signals are sent into the spectrometer for signal analysis to obtain a tomographic image;

the polarization controller is an optical fiber device and has the function of changing the polarization state of light in the optical fiber by twisting and stretching the optical fiber;

the fiber pigtail is a light connector and is used as an interface between the interferometer and the sample arm light path and the reference arm light path respectively.

The reference arm light path is composed of a second collimating mirror, a dispersion compensating rod, a right angle reflecting mirror and a delay reflecting mirror, and the reference arm light path is used for forming reference light with the same optical path as the sample arm light path so as to form an interference signal with the return light of the sample arm.

And the second collimating lens is an optical lens, the focal length range is 5 mm-25 mm, and the numerical aperture is not more than 0.5.

The dispersion compensation rod is an optical device, and is made of optical glass, and the dispersion compensation rod is used for compensating dispersion difference between a reference arm light path and a sample arm light path, so that interference signals can reach the maximum value.

The right angle reflector is an optical reflector, can reflect light rays incident on the right angle reflector in a direction of 180 degrees, has a reflectivity of not less than 80 percent, and has the function of folding the light path and reducing the volume of the light path of the reference arm.

The delay reflector is an optical reflector, has reflectivity not lower than 90%, and is used for reflecting incident light and forming reference light with the same optical path as that of the sample arm, and the delay reflector can move back and forth along the optical axis to compensate the difference of the eye axis lengths of different people.

The spectrometer is used for carrying out Fourier change on the formed interference signals to obtain a tomographic image.

The invention has the advantages and positive effects that:

1. the large-vision retina examination device adopts a high-integration illumination module, and utilizes the annular condenser to collect light on the crystal and form a light ring, so that the light can be uniformly dispersed at the fundus to form fundus illumination exceeding 130-degree visual field. The illumination field is determined by the light emission angle of the light source, and increases with the increase of the light emission angle of the light source. The invention removes the light guide optical fiber and the light guide prism used in the prior art, and reduces the manufacturing cost and the adjustment difficulty; the LED light source is used for replacing a halogen lamp light source, so that the power consumption and the heating value of the product are greatly reduced.

2. The large-field retina examination device integrates the fundus imaging light path of a large field of view and the sample arm light path of optical coherence tomography in one probe, so that the function of performing optical coherence tomography on the fundus while performing real-time large-field color imaging or fluorescent radiography imaging on the fundus is realized. The two imaging modes are not mutually interfered, so that the full-scale screening of the single equipment on the fundus diseases is realized, and the method is particularly suitable for early diagnosis and postoperative review of infant fundus retinopathy.

3. The large-view-field fundus imaging light path of the large-view-field retina examination device adopts the mode of switching the optical filters to realize fluorescence contrast imaging, and solves the problem that a probe needs to be replaced in the prior art. Moreover, the probe realized by the invention has the characteristic of high integration, and the volume and the weight of the probe have obvious advantages compared with the prior art.

Drawings

FIG. 1 is a schematic illustration of an optical structure of the present invention;

FIG. 2 is a schematic view of the light of the illumination module of the present invention traveling in the human eye;

fig. 3 is a color fundus image obtained by the present invention;

FIG. 4 is a fluoroscopic image obtained according to the present invention;

fig. 5 is an optical coherence tomographic image obtained by the present invention.

Detailed Description

Specific embodiments of the invention are described in further detail below with reference to the accompanying drawings:

the apparatus of this embodiment consists essentially of a probe and an interferometer. As shown in fig. 1, the probe is composed of an illumination module, a fundus imaging optical path and a sample arm optical path.

The lighting module is composed of an LED light source 3, a light homogenizing sheet 2 and an annular condensing lens 1, wherein the annular condensing lens is formed by alternately arranging 8 white light LEDs and 8 blue light LEDs which are packaged in the same way into a circular ring with the diameter of 12mm, and the front of the annular condensing lens is provided with an annular light homogenizing sheet. When the LED light source emits light, the light homogenizing sheet can be regarded as an annular luminous body with uniform brightness in all directions. An annular condenser lens is disposed in front of the light homogenizing sheet to direct light through the contact lens of the ocular lens set and onto the surface of the human eye lens 26 to form a light ring. These rays continue to propagate forward and will spread out at the fundus to form a uniform illumination, as shown in fig. 2. Since the central region 27 of the crystal is not illuminated by the light 28, it is possible to avoid stray light from being formed by reflection of illumination light into the fundus imaging optical path.

The fundus imaging light path is composed of an ocular lens group, an imaging objective lens 8, a dichroic mirror 9, a low-pass filter 10, a fluorescent filter 25 and an imaging camera 24. The light emitted by the illumination module is collected by the ocular lens group after being reflected by the ocular fundus, and an intermediate image plane R is formed behind the ocular lens group. The imaging objective lens performs secondary imaging on the intermediate image plane, and forms a final fundus image R' on the imaging camera through the dichroic mirror and the low-pass filter.

The sample arm light route is composed of an ocular lens group, an imaging objective lens, a dichroic mirror, a high-pass filter 11, a scanning objective lens 13, a scanning galvanometer 14 and a first collimating lens 15, wherein the ocular lens group, the imaging objective lens and the dichroic mirror are shared with a fundus imaging light path. The first collimating lens bends the light rays emitted by the optical fiber tail fiber of the interferometer into parallel light rays, the parallel light rays are projected onto the scanning objective lens through the scanning vibrating lens, and the scanning vibrating lens converges the light rays on the rear focal plane of the scanning objective lens to form a light spot. The scanning galvanometer can periodically change the reflection angle, so that the position of the light spot on the focal plane can also be changed along with the change of the reflection angle, and a scanning image plane R is formed. R ' is optically conjugated with the intermediate image plane R ' through the high pass filter, the dichroic mirror and the imaging objective lens, and R ' is optically conjugated with the fundus of the human eye through the ocular lens group, so that the scanning image plane R ' is also optically conjugated with the fundus of the human eye, and then the light spot on R ' is also a light spot at the fundus of the human eye. Thus, the light spot can be scanned on the fundus by changing the reflection angle of the scanning galvanometer. The fundus can reflect the optical point, and the light can return to the fiber pigtail through the optical path of the sample arm and enter the interferometer.

The LED light source is a patch type LED, the white light LED is a color imaging light source, the color temperature range is 5000K, and the color rendering index is 92%; the blue light LED is a fluorescence contrast light source, and the central wavelength is 475nm.

The light homogenizing sheet is an acrylic plate with frosted two surfaces, the surface roughness is 300 meshes, and the light transmittance is 80%.

The annular condenser is an optical lens, one surface is a plane, the radius of curvature of the other surface is 6.5mm, and the material is PMMA.

The ocular lens group consists of a contact lens 5, a conical lens 6 and an ocular objective lens 7, and is used for collecting light reflected by eyeground to form an intermediate image surface R with better quality and low distortion.

The contact lens is an optical lens and is required to be contacted with the cornea 4 of a human eye during operation. Therefore, the curvature radius is similar to that of the cornea of human eyes, and is 8mm, and the material is ZLAF optical glass.

The conical lens is a conical optical lens, the material of the conical lens is LaK optical glass, and the conical lens and the contact lens form a cemented lens for eliminating chromatic aberration of a part of human eyes. The diameter of the glued part of the conical mirror and the contact lens is 5mm, the cone angle is 40 degrees, and enough installation space can be provided for the lighting module.

The objective lens is a 2-piece optical lens, and has the function of eliminating aberration of human eyes, mainly spherical aberration, coma aberration, chromatic aberration and distortion, wherein one piece is a double-cemented lens.

The imaging objective lens is a 3-piece optical lens, the combined focal length range is 30mm, and the imaging objective lens comprises 1-piece double-cemented lens and 1-piece triple-cemented lens and is used for eliminating chromatic aberration and secondary chromatic aberration of human eyes. The imaging objective lens can move back and forth along the imaging optical axis to compensate individual differences of diopter of human eyes, so that the imaging image plane R' just falls on the imaging camera to form a clear fundus retina image, as shown in fig. 3. Furthermore, the imaging objective lens also has image space telecentricity, and telecentricity is 1.5 °.

The dichroic mirror is an optical lens and has a working angle of 45 degrees. The function of the lens is that the lens reflects visible light and transmits near infrared light, and the near infrared light are transmitted in mutually perpendicular directions after passing through the lens, so that the purpose of separation is achieved.

The low-pass filter is an optical filter, and the working angle is 0 degree. The function of the infrared light shielding device is to cut off near infrared light while transmitting visible light, and prevent the near infrared light from entering an imaging camera to interfere image formation.

The fluorescent filter is an optical filter, and the working angle is 0 degree. The effect is to transmit green fluorescence excited by blue light to irradiate fluorescein and cut off light of other wave bands to form a high contrast fluorescence contrast image, as shown in fig. 4.

The low-pass filter and the fluorescent filter can be switched through a mechanical structure, and only one of the low-pass filter and the fluorescent filter can be arranged in a fundus imaging optical path at a time. When the fundus is subjected to color imaging, a low-pass filter is used; and a fluorescence filter is used for fluorescence imaging of the fundus.

The imaging camera is a CMOS camera, the photosensitive area is 1/1.8 inch, the resolution is not 300 ten thousand pixels, and the imaging camera is positioned on an image plane R' of a fundus imaging light path to form an image.

The first collimating lens is an optical lens, the focal length range is 7.5mm, and the numerical aperture is 0.3.

The scanning galvanometer is a scanning reflecting mirror, the reflecting angle can be changed periodically, the scanning frequency is 1KHz, and the scanning angle is not more than +/-10 degrees.

The scanning objective lens is a 5-piece optical lens, and the combined focal length range is 50mm. The scanning objective lens also has the characteristics of telecentricity at the image space and low distortion, wherein the telecentricity is 1 DEG and the distortion is 3%.

The high-pass filter is an optical filter, and the working angle is 0 degree. The function of the infrared light-emitting device is to cut off visible light while transmitting near infrared light, and prevent the visible light from entering the interferometer to interfere due to fundus reflection.

The interferometer is composed of a weak coherent light source 20, a 2x2 optical fiber coupler 19, a polarization controller 17, an optical fiber tail fiber 16, a reference arm light path and a spectrometer 21, and is used for carrying out optical coherence tomography on fundus retina.

The optical weak coherent light source is a super-radiation light emitting diode (SLED), the central wavelength of the optical weak coherent light source is 850nm, and the bandwidth of the optical weak coherent light source is 60nm.

The 2x2 optical fiber coupler is an optical fiber device and is a core device of an interferometer. The device is provided with 4 tail fibers which are respectively connected into a weak coherent light source, a sample arm light path, a reference arm light path and a spectrometer. The interferometer has the functions that light rays emitted by the weak coherent light source can be respectively guided into the sample arm light path and the reference arm light path according to a certain proportion, return light of the two light paths is collected to form interference signals, and then the interference signals are sent into the spectrometer for signal analysis to obtain a tomographic image.

The polarization controller is a double-paddle dial type, the diameters of the two paddles are 22mm, two 1/4 wave plates aiming at a 840nm light source are formed according to the winding number of the optical fiber, and the polarization state of light rays in the optical fiber can be adjusted at will.

The reference arm light path is composed of a second collimating mirror 18, a dispersion compensating rod 12, a right angle reflecting mirror 23 and a delay reflecting mirror 22, and the reference arm light path is used for forming an interference signal between reference light with the same optical path as the sample arm light path and return light of the sample arm.

The second collimating lens is an optical lens, the focal length range is 7.5mm, and the numerical aperture is 0.3.

The dispersion compensation rod is an optical device, the material is K9 glass, and the length is 30mm. The function of the device is to compensate the dispersion difference between the reference arm light path and the sample arm light path, so as to ensure that the interference signal can reach the maximum value.

The right angle reflector is an optical reflector, and can reflect light rays incident on the right angle reflector in a direction of 180 degrees, and the reflectivity is 92%. The function of the device is to fold the light path and reduce the volume of the reference arm light path.

The delay reflecting mirror is an optical reflecting mirror, and the reflectivity is 98%. The function of the device is to reflect the incident light and form the reference light with the same optical path as the sample arm optical path. The delay mirror can move back and forth along the optical axis to compensate for the difference in length of the eye axis between different persons.

The spectrometer is used for carrying out Fourier transformation on the formed interference signals to obtain a tomographic image, as shown in fig. 5.

Although the embodiments of the present invention and the accompanying drawings have been disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the embodiments and the disclosure of the drawings.

Claims

1. A large field retinal examination apparatus, characterized in that: the probe consists of a probe and an interferometer, wherein the interferometer is connected with a sample arm light path in the probe through an optical fiber tail fiber in the interferometer;

the interferometer is used for carrying out optical coherence tomography on the retina of the fundus;

the illumination module consists of LED light sources, light homogenizing sheets and annular condensing lenses, wherein a plurality of LED light sources are distributed in a circular shape, the annular light homogenizing sheets are arranged in front of the formed circular ring, the annular condensing lenses are arranged in front of the light homogenizing sheets, and the annular condensing lenses project light rays on the surface of human eye crystals after passing through contact lenses of an ocular lens group to form a light ring;

the fundus imaging light path consists of an ocular lens group, an imaging objective lens, a dichroic mirror, a low-pass filter, a fluorescent filter and an imaging camera, wherein light rays emitted by the illumination module are collected by the ocular lens group after being reflected by the fundus, an intermediate image plane R is formed behind the light rays, the imaging objective lens can perform secondary imaging on the intermediate image plane, and a final fundus image R' is formed on the imaging camera through the dichroic mirror and the low-pass filter or the fluorescent filter;

after the light emitted by the optical fiber tail fiber of the interferometer is bent into parallel light by the first collimating mirror, the parallel light is projected onto the scanning objective lens through the scanning galvanometer, the scanning objective lens converges the light on the rear focal plane of the scanning objective lens to form a light spot, the position of the light spot on the focal plane changes along with the change of the reflection angle of the scanning galvanometer to form a scanning image plane R ', the light spot at any position in the R ', through the high-pass filter, the dichroic mirror and the imaging objective lens, forms another equivalent light spot at the fundus of the human eye, the position of the equivalent light spot also changes along with the change of the position of the light spot in the R ', the fundus can reflect the equivalent light spot, and the light returns to the optical fiber tail fiber through the optical path of the sample arm to enter the interferometer.

2. A large visual field retinal examination apparatus as claimed in claim 1, wherein: the length of the probe is not more than 250mm, and the weight of the probe is not more than 3kg.

3. A large visual field retinal examination apparatus as claimed in claim 1, wherein: the LED light source is a patch type LED and consists of white light LEDs and blue light LEDs which are arranged at intervals, the white light LEDs are color imaging light sources, the color temperature range is 4000K-5500K, and the color rendering index is not lower than 90%; the blue light LEDs are fluorescence contrast light sources, the central wavelength range is 460-490 nm, and the number of each LED is not less than 6;

the light homogenizing sheet is an acrylic plate or frosted glass with a frosted surface, the surface roughness is not lower than 1000 meshes, and the light transmittance is not lower than 70%;

the annular condensing lens is an optical lens, one surface is a plane, and the radius of curvature of the other surface is 2 mm-10 mm.

4. A large visual field retinal examination apparatus as claimed in claim 1, wherein: the ocular lens group consists of a contact lens, a conical lens and an ocular objective lens, and is used for collecting light reflected by eyeground to form an intermediate image plane R;

the contact lens is an optical lens, and the curvature radius of the contact lens is similar to that of a cornea of a human eye;

the conical lens is a conical optical lens, the material of the conical lens is different from that of the contact lens, the conical lens and the contact lens form a cemented lens for eliminating chromatic aberration of a part of human eyes, and the illumination module is arranged on the outer ring of the conical lens;

the objective lens is a 1-group optical lens and is used for eliminating aberration of human eyes, wherein the aberration mainly comprises spherical aberration, coma aberration, chromatic aberration and distortion.

5. A large visual field retinal examination apparatus as claimed in claim 1, wherein: the imaging objective lens is 1 group of optical lenses, the focal length range is 10 mm-100 mm, the imaging objective lens at least comprises 1 glued lens, and the imaging objective lens moves back and forth along an imaging optical axis and is used for compensating individual differences of diopter of human eyes, so that an imaging image plane R' just falls on an imaging camera to form a clear fundus retina image;

the dichroic mirror is an optical lens and has a working angle of 45 degrees, and has the functions of reflecting visible light and transmitting near infrared light at the same time, so that the visible light and the near infrared light propagate in mutually perpendicular directions after passing through the lens, and the purpose of separation is achieved;

the low-pass filter is an optical filter, the working angle is 0 degrees, and the low-pass filter is used for transmitting visible light and simultaneously cutting off near infrared light so as to prevent the near infrared light from entering an imaging camera to interfere an image;

the fluorescent filter is an optical filter, the working angle is 0 degrees, and the fluorescent filter has the functions of transmitting green fluorescence excited by blue light to irradiate fluorescein and cutting off light of other wave bands to form a high-contrast fluorescent contrast image;

6. The large-field retinal examination apparatus according to claim 5, wherein: the low-pass filter and the fluorescent filter are switched to be used, and the low-pass filter is used when only one of the low-pass filter and the fluorescent filter is in a fundus imaging light path at each time to perform color imaging on the fundus; when performing fluorescence imaging on the fundus, a fluorescence filter is used.

7. A large visual field retinal examination apparatus as claimed in claim 1, wherein: the first collimating lens is an optical lens, the focal length range is 5 mm-25 mm, and the numerical aperture is not more than 0.5;

the scanning vibrating mirror is a scanning reflecting mirror, the reflection angle can be changed periodically, the scanning frequency is not lower than 100Hz, and the scanning angle is not more than +/-20 degrees;

the scanning objective lens is 1 group of optical lenses, and the focal length range is 20 mm-100 mm;

8. A large visual field retinal examination apparatus as claimed in claim 1, wherein: the interferometer consists of a weak coherent light source, a 2x2 optical fiber coupler, a polarization controller, an optical fiber tail fiber, a reference arm light path and a spectrometer,

the weak coherent light source is a super-radiation light-emitting diode, the central wavelength range of the weak coherent light source is 780-1100 nm, and the bandwidth is not narrower than 40nm;

the 2x2 optical fiber coupler is an optical fiber device and is provided with 4 tail fibers which are respectively connected into a weak coherent light source, a sample arm light path, a reference arm light path and a spectrometer; the interferometer is used for guiding light rays emitted by the weak coherent light source into a sample arm light path and a reference arm light path respectively according to a set proportion, collecting return light of the two light paths to form interference signals, and sending the interference signals into the spectrometer for signal analysis to obtain a tomographic image;

the optical fiber tail fiber is a light connector and is used as an interface between the interferometer and a sample arm light path and a reference arm light path respectively;

9. The large visual field retinal examination apparatus according to claim 8, wherein: the second collimating lens is an optical lens, the focal length range is 5 mm-25 mm, and the numerical aperture is not more than 0.5;

the dispersion compensation rod is an optical device, is made of optical glass, and has the function of compensating dispersion difference between a reference arm light path and a sample arm light path, so that interference signals are ensured to reach the maximum value;

the right-angle reflecting mirror is an optical reflecting mirror, can reflect light rays incident on the right-angle reflecting mirror in a direction of 180 degrees, has the reflectivity of not less than 80 percent, and has the function of folding the light path and reducing the volume of the light path of the reference arm;

the delay reflector is an optical reflector, has the reflectivity not lower than 90 percent, and has the functions of reflecting incident light rays and forming reference light with the same optical path as that of a sample arm optical path, and the delay reflector moves back and forth along an optical axis to compensate the difference of the lengths of eye axes of different people;