A fundus fluorescence angiography apparatus and method

Abstract

The application belongs to the technical field of ophthalmic medical equipment and relates to a fundus fluorescence imaging device which comprises an ocular lens, an automatic eye searching module, an illumination diaphragm, a rotating speed modulation module, a dichroic mirror, an automatic focusing and fixation module, a function switching module, a rotating speed recording module, an imaging lens group and an imaging receiving module. The automatic eye searching module is arranged on the two sides of the ocular lens. The illumination diaphragm, the dichroic mirror, the function switching module, the imaging lens group and the imaging receiving module are sequentially arranged in front of the ocular lens. The rotating speed modulation module is arranged on the side of the illumination diaphragm. The rotating speed recording module is arranged on the side of the function switching module. The automatic focusing and fixation module is reflected by the dichroic mirror and then sequentially passes through the illumination diaphragm and the ocular lens to act on the human eye. The fundus fluorescence imaging device integrates the functions of FFA, ICGA, FAF, red-free photographing and ordinary fundus color photographing and the like, the function switching is completed in the device and no additional configuration is needed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ophthalmic medical equipment, and relates to a measurement technology, in particular to an ocular fundus fluorescence imaging device and method. BACKGROUND

[0002] Ocular fundus fluorescence imaging technology is an important examination technology in the field of ophthalmology, and its principle is to inject a special contrast agent into a vein quickly. The contrast agent can develop in the ocular fundus blood vessels. By using a contrast machine or an ocular fundus camera, the developed image can be recorded to analyze the ocular fundus diseases. After the contrast agent enters the ocular fundus blood vessels through blood circulation, the ocular fundus can be photographed through the pupil. Doctors can analyze the ocular fundus diseases according to the developed image, such as judging whether the retinal arteries and veins are blocked, blood vessels are leaked, and the macula is present.

[0003] With the continuous development of ophthalmology and the continuous progress of technology, the ocular fundus fluorescence imaging technology is subdivided into fluorescein fundus angiography (FFA), indocyanine green angiography (ICGA), and fundus autofluorescence (FAF). Each of the three has its own advantages and the results are complementary. If all the fluorescence functions are integrated into one, it is a great challenge to the structural design of the device.

[0004] The existing ocular fundus fluorescence imaging device is mainly based on two technologies:

[0005] One is based on the principle of laser confocal scanning fundus mirror, such as the Heidelberg Spectralis HRA and OPTOS California devices, which use laser as the excitation light source. The price is expensive, and a laser scanning component needs to be built in. The bandwidth of the laser is narrow, and the bandwidth range is limited by the manufacturing process to be too narrow or too wide, making it difficult to adjust the excitation light source to the best state of the fluorescence image. Each item of ocular fundus fluorescence imaging function needs to set up a laser with a corresponding excitation wavelength. When multiple functions are integrated, the complexity of the optical design of the device is greatly improved, and the cost of the device also increases greatly, which is difficult to popularize.

[0006] Another device is based on the ocular fundus camera technology, such as the ocular fundus fluorescence imaging machine produced by Topcon Company, which uses halogen lamp or xenon lamp as the excitation light source. The light source has high power consumption, complex installation process, high maintenance cost and short service life, and needs to be replaced frequently. Moreover, the device uses the optical design of the traditional ocular fundus camera, and uses a black dot plate as a component to eliminate system reflection stray light, that is, a circular light barrier is arranged at the conjugate position of the stray light reflection surface, so that the stray light cannot pass through, and part of the imaging light passes through. This scheme causes the brightness of the collected image to be uneven, with a dark center area, which needs to be processed by software.

[0007] Therefore, it is necessary to design a fundus fluorescence imaging device integrating all fluorescent functions. SUMMARY

[0008] The present application aims at overcoming the deficiencies of the prior art, and provides a multifunctional fundus fluorescence imaging device with reasonable structure design, low cost and long life cycle.

[0009] The present application solves the technical problems by the following technical solutions:

[0010] A fundus fluorescence imaging device, characterized in that: comprising an ocular lens, an automatic eye searching module, an illumination diaphragm, a rotation speed modulation module, a dichroic mirror, an automatic focusing and fixation module, a function switching module, a rotation speed recording module, an imaging lens group and an imaging receiving module, the automatic eye searching module is symmetrically arranged on both sides of the ocular lens, and the illumination diaphragm, the dichroic mirror, the function switching module, the imaging lens group and the imaging receiving module are coaxially arranged in front of the ocular lens from back to front, the rotation speed modulation module is arranged on the side of the illumination diaphragm, and the rotation speed recording module is arranged on the side of the function switching module, the automatic focusing and fixation module is reflected by the dichroic mirror and then passes through the illumination diaphragm and the ocular lens to act on the human eye in sequence.

[0011] Moreover, the illumination diaphragm is rotationally arranged on the optical axis center, the rotation speed is controlled by the rotation speed modulation module, the illumination diaphragm is provided with a light blocking area and a light passing area, the back of the light blocking area is a conical surface, and an irregular pattern capable of reducing light reflection is engraved on the conical surface.

[0012] Moreover, the irregular pattern capable of reducing light reflection is a light absorption thread.

[0013] Moreover, a light absorption material is sprayed on the irregular pattern of the conical surface.

[0014] Moreover, the minimum area of the light blocking area of the illumination diaphragm is the minimum area satisfying the elimination of reflected stray light.

[0015] Moreover, the function switching module is rotationally arranged on the optical axis center, the rotation speed is recorded in real time by the rotation speed recording module, and the function switching module comprises an illumination switching assembly, an illumination filter assembly, an illumination lamp PCB and an imaging filter assembly which are sequentially arranged from back to front, and through holes are arranged at the center positions of the illumination switching assembly, the illumination filter assembly and the illumination lamp PCB.

[0016] The illumination switching assembly is provided with a light blocking area and a light passing area.

[0017] N equal-area filter areas are arranged on the illumination filter assembly, and illumination filters are arranged on the filter areas, and the area of the filter area is adapted to the area of the light transmission area on the illumination switching assembly;

[0018] The illumination lamp PCB is composed of a plurality of full-spectrum white light LEDs closely arranged on a circuit board, and one side of the full-spectrum white light LEDs arranged on the illumination lamp PCB faces the illumination filter assembly;

[0019] The functional imaging filters are uniformly distributed along the circumference on the imaging filter assembly, each functional imaging filter has the same size as the through hole, the center of the functional imaging filter under rotation coincides with the optical axis, and the corresponding functional imaging filter is switched according to the position change of the illumination switching assembly.

[0020] Moreover, the imaging receiving module is a surface array photoelectric converter.

[0021] An eye fundus fluorescence imaging method, characterized in that it comprises the following steps:

[0022] Step 1: moving the eye fundus fluorescence imaging device to a reset position through a three-dimensional platform;

[0023] Step 2: confirming the functions needed to be run on the eye fundus fluorescence imaging device, and switching the illumination switching assembly, the illumination filter assembly and the imaging filter assembly to the corresponding positions by the internal function switching module of the eye fundus fluorescence imaging device, and keeping the relative positions fixed along the optical axis;

[0024] Step 3: starting measurement, and moving the eye fundus fluorescence imaging device to the front of the measured eye by the automatic eye searching module, and gradually moving to the working position;

[0025] Step 4: opening the automatic focusing and fixation module to stabilize the visual axis direction of the measured eye, and making the image clear by automatic focusing;

[0026] Step 5: if the image is normal, normal collection is performed; if the image appears stray light, the rotation speed recording module feeds back to the rotation speed modulation module to adjust the rotation speed matching, so that the illumination diaphragm and the function switching module keep the best matching position and rotate synchronously, and then image collection is performed again;

[0027] Step 6: after the collection is completed, image analysis is performed, and the device returns to the reset position.

[0028] The advantages and beneficial effects of the present application are as follows:

[0029] The present eye fundus fluorescence imaging device uses full-spectrum LEDs to replace halogen lamp light sources or laser light sources, has uniform spectrum, long device life, high stability and low cost;

[0030] The fundus fluorescence imaging device uses an optimized feedback type stray light elimination design, ensures that the fundus fluorescence imaging is not affected by external factors, and the image brightness is uniform and stable, and the image details are not distorted.

[0031] The fundus fluorescence imaging device integrates FFA, ICGA, FAF, red-free photographing and ordinary fundus color photographing and other fundus examination functions, and the function switching is completed in the device, without additional configuration. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a structural principle schematic diagram of the present application;

[0033] Figure 2 It is a structural schematic diagram of the illumination diaphragm of the present application;

[0034] Figure 3 It is a structural schematic diagram of the function switching module of the present application;

[0035] Figure 4 It is a structural schematic diagram of the illumination switching assembly of the present application;

[0036] Figure 5 It is a structural schematic diagram of the illumination filter assembly of the present application;

[0037] Figure 6 It is a structural schematic diagram of the illumination lamp PCB of the present application;

[0038] Figure 7 It is a structural schematic diagram of the imaging filter assembly of the present application.

[0039] REFERENCE NUMERALS

[0040] 1-human eye, 2-automatic eye searching module, 3-ocular lens, 4-illumination diaphragm, 5-rotation speed modulation module, 6-dichroic mirror, 7-automatic focusing and fixation module, 8-function switching module, 9-rotation speed recording module, 10-imaging lens group, 11-imaging receiving module, 12-illumination switching assembly, 13-illumination filter assembly, 14-illumination lamp PCB, 15-imaging filter assembly, 16-light blocking area, 17-light passing area. DETAILED DESCRIPTION

[0041] The present application will be further described in detail below through specific examples, the following examples are only descriptive, not limiting, and cannot limit the protection scope of the present application.

[0042] As Figure 1As shown, an ocular fundus fluorescence imaging device is arranged on a three-dimensional platform which can move in X, Y and Z directions, and is used for taking ocular fundus fluorescence imaging photograph and video of a human eye 1, and the device has the following innovative points: the device comprises an ocular lens 3, an automatic eye searching module 2, an illumination diaphragm 4, a rotating speed modulation module 5, a dichroic mirror 6, an automatic focusing and fixation module 7, a function switching module 8, a rotating speed recording module 9, an imaging lens group 10 and an imaging receiving module 11, the automatic eye searching module is symmetrically arranged on both sides of the ocular lens, and is used for calculating the relative position information of the human eye and the device in real time, and feeding back the position of the three-dimensional platform in X, Y and Z directions to adjust the working position of the device; the illumination diaphragm, the dichroic mirror, the function switching module, the imaging lens group and the imaging receiving module are coaxially arranged in sequence from back to front in front of the ocular lens, the illumination diaphragm and the function switching module can rotate along the optical axis center of the device, the rotating speed modulation module is arranged on the side of the illumination diaphragm to control the rotating speed thereof, the rotating speed recording module is arranged on the side of the function switching module to record the rotating speed thereof, the automatic focusing and fixation module projects the automatic focusing beacon and the fixation pattern to the human eye through the illumination diaphragm and the ocular lens in sequence after being reflected by the dichroic mirror, and is used for compensating the ametropia of different subjects to obtain the best ocular fundus image; the fixation pattern can stabilize the visual axis direction of the subject to ensure the quality of the ocular fundus image.

[0043] As shown in the figure, Figure 2 The illumination diaphragm is provided with a light blocking area 16 and a light passing area 17, according to the optical design of the ocular fundus fluorescence imaging device, the minimum area of the light blocking area of the illumination diaphragm is determined by the size of the reflected stray light area superimposed on the ocular fundus image collected by the imaging receiving module, in order to improve the utilization rate of the illumination light, the light blocking area should be set to the minimum area to eliminate the reflected stray light.

[0044] As shown in the figure, Figure 2 The back of the light blocking area is a conical surface, the slope is selected according to the simulation results, and the light reflected into the imaging system by the light blocking area is reduced to the maximum extent, and irregular patterns that can reduce light reflection are engraved on the conical surface. The irregular patterns can be light absorption threads or other irregular patterns that can reduce light reflection.

[0045] In order to further reduce the reflection of the illumination light, the irregular patterns on the conical surface are also sprayed with light absorbing materials.

[0046] The purpose of setting the irregular patterns that can reduce light reflection on the conical surface and setting the light absorbing materials on the irregular patterns is to eliminate the reflected stray light formed by the functional illumination light on the back surface of the illumination diaphragm, and to avoid affecting the imaging quality.

[0047] As shown in the figure, Figures 3-7As shown, the function switching module includes, from back to front, an illumination switching assembly 12, an illumination filter assembly 13, an illumination lamp PCB 14, and an imaging filter assembly 15, and a through hole is arranged at the center of the illumination switching assembly, the illumination filter assembly, and the illumination lamp PCB.

[0048] The illumination switching assembly, the illumination filter assembly, and the illumination lamp PCB are closely arranged, the center of the filter is coincident with the optical axis, and the corresponding functional imaging filter is switched according to the change of the position of the illumination switching assembly. The function switching module can rotate along the center of the optical axis of the device, and the rotation speed is recorded in real time by the rotation speed recording module.

[0049] The illumination switching assembly is provided with a light blocking area and a light passing area.

[0050] The illumination filter assembly is provided with N equal-area filter areas, different illumination filters can be arranged according to the requirements of different functions on the illumination light wave band, and the area of the filter area is matched with the area of the light passing area on the illumination switching assembly. In this embodiment, the illumination filters include FFA illumination filter, ICGA illumination filter, FAF illumination filter, red-free filter, Color illumination filter, and common filter, and each illumination filter is in a fan-shaped structure.

[0051] The illumination lamp PCB 14 is provided with closely arranged full-spectrum white light LEDs, the spectral composition of the LEDs is uniform, and the wave band coverage area is wide. The illumination light is divided into N functional illumination lights of different wave bands through the illumination filter assembly, the light passing area of the illumination switching assembly can pass one of the N functional illumination lights, and the light blocking area blocks other functional illumination light. The illumination switching assembly changes the relative position of the light passing area, the illumination filter assembly, and the illumination lamp PCB to realize the switching of the functional illumination light.

[0052] The imaging filter assembly is provided with functional imaging filters which are evenly distributed along the circumference. In this embodiment, the functional imaging filters include FFA functional imaging filter, ICGA functional imaging filter, FAF functional imaging filter, red-free functional filter, Color functional imaging filter, and common functional filter, the size of each functional imaging filter is the same as the through hole, the center of the functional imaging filter below is coincident with the optical axis, and the corresponding functional imaging filter is switched according to the change of the position of the illumination switching assembly.

[0053] When the device determines the function to be operated, the illumination switching assembly and the imaging filter assembly are switched to the corresponding functional position. The functional illumination light on the illumination lamp PCB is emitted by the function switching module, passes through the dichroic mirror, the illumination diaphragm, and the ocular lens to enter the human eye, the illuminated fundus forms imaging light which returns to the device, and the imaging light passes through the ocular lens, the imaging diaphragm, the dichroic mirror, the through hole, the functional imaging filter, and the imaging lens group to be collected by the imaging receiving module to form an image.

[0054] The functional illumination light is offset from the main optical axis of the device, forming off-axis illumination. The functional illumination light will generate reflected stray light on both the front and back surfaces of the eyepiece. The light-blocking part of the illumination aperture is set on the light path of the reflected stray light to avoid forming interfering bright spots on the image. The light-passing area is illuminated by the functional illumination light to illuminate the fundus. The imaging light excited by the fundus returns to the optical system to form an image.

[0055] The functional illumination light is off-axis illumination. To ensure uniform brightness in the acquired image, the function switching module rotates at a constant speed along the optical axis, with the rotation speed recorded in real time by the speed recording module. The illumination aperture maintains a fixed relative position with the function switching module and rotates along with it, with its rotation speed controlled by the speed modulation module. If the exposure time of the imaging receiving module is T, then the relationship between the rotation speed w and the exposure time can be expressed by the following formula:

[0056] T = N / w

[0057] Where N is the number of rotations, and can only be a positive integer;

[0058] During the image exposure time, the illumination stop and the function switching module maintain a fixed relative position and complete an integer number of rotation cycles to ensure uniform and stable image brightness.

[0059] During actual operation, the function switching module is inevitably affected by external factors, causing fluctuations in its rotation speed. This leads to changes in the relative position of the illumination aperture and the function switching module, causing previously blocked stray light to reappear and affecting image quality. Feature pattern recognition is performed on the acquired fundus images. When abnormally bright saturated areas appear in the image, it is determined to be a rotation speed mismatch. A feedback signal is issued, feeding back the rotation speed of the function switching module, which is recorded in real time by the rotation speed recording module, to the rotation speed modulation module that controls the illumination aperture. The rotation speed of the illumination aperture is adjusted until the feedback signal from the image feature pattern recognition disappears. The relative position of the illumination aperture and the function switching module is restored, and the equipment operates normally. The entire process forms a closed-loop feedback adjustment, requiring no manual intervention and improving the overall stability of the equipment.

[0060] The speed recording module and speed modulation module can be speed controllers such as electronic encoders or photoelectric encoders. The imaging receiving module can be a CMOS, CCD, or other area array photoelectric conversion device.

[0061] An innovative method for fundus fluorescein angiography includes the following steps:

[0062] Step 1: Move the fundus fluorescein angiography device to the reset position using a 3D platform;

[0063] Step 2, confirm the function to be operated on the fundus fluorescence imaging device, the internal function switching module of the fundus fluorescence imaging device switches the illumination switching assembly, the illumination filter assembly and the imaging filter assembly to the corresponding position, and keeps the relative position fixed along the optical axis;

[0064] Step 3, start measurement, the automatic eye searching module moves the fundus fluorescence imaging device to the front of the measured eye and gradually moves to the working position;

[0065] Step 4, the automatic focusing and fixation module is opened, the direction of the visual axis of the measured eye is stabilized, and the automatic focusing makes the image clear;

[0066] Step 5, if the image is normal, normal collection is performed; if stray light appears in the image, the rotation speed recording module feeds back to the rotation speed modulation module for rotation speed matching adjustment, so that the illumination diaphragm and the function switching module keep the best matching position synchronous rotation, and then image collection is performed again;

[0067] Step 6, after the collection is completed, image analysis is performed, and the device returns to the reset position.

[0068] Although the embodiments of the present application and the drawings are disclosed for the purpose of illustration, those skilled in the art can understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present application and the appended claims, therefore, the scope of the present application is not limited to the disclosed content of the embodiments and the drawings.

Claims

1. A fundus fluorescein angiography device, characterized in that: The device includes an eyepiece, an automatic eye-finding module, an illumination diaphragm, a rotation speed modulation module, a dichroic mirror, an autofocus and fixation module, a function switching module, a rotation speed recording module, an imaging lens assembly, and an imaging receiving module. Automatic eye-finding modules are symmetrically arranged on both sides of the eyepiece. From back to front, an illumination diaphragm, a dichroic mirror, a function switching module, an imaging lens assembly, and an imaging receiving module are arranged coaxially with the eyepiece in front of it. A rotation speed modulation module is located on the side of the illumination diaphragm, and a rotation speed recording module is located on the side of the function switching module. The autofocus and fixation module, after reflection by the dichroic mirror, acts on the human eye through the illumination diaphragm and the eyepiece. The illumination aperture is rotated at the center of the optical axis, and the rotation speed is controlled by the rotation speed modulation module. The illumination aperture is provided with a light-blocking area and a light-passing area. The back of the light-blocking area is a conical surface, and irregular patterns that can reduce light reflection are engraved on the conical surface. The function switching module is rotated at the center of the optical axis, and the rotation speed is recorded in real time by the rotation speed recording module. The function switching module includes an illumination switching component, an illumination filter component, an illumination lamp PCB and an imaging filter component arranged sequentially from back to front. A through hole is provided at the center of the illumination switching component, the illumination filter component and the illumination lamp PCB. The lighting switching component is provided with a light-blocking area and a light-transmitting area; The lighting filter assembly is provided with N filter areas of equal area, and each filter area is provided with an lighting filter. The area of ​​the filter area is adapted to the area of ​​the light-transmitting area on the lighting switching assembly. The lighting PCB is composed of several full-spectrum white LEDs arranged closely on the circuit board, with the side of the lighting PCB containing the full-spectrum white LEDs facing the lighting filter assembly; Functional imaging filters are evenly distributed along the circumference of the imaging filter assembly. The size of each functional imaging filter is the same as that of the through hole. When rotated, the center of the lower functional imaging filter coincides with the optical axis, and the corresponding functional imaging filter is switched as the position of the illumination switching assembly changes.

2. The fundus fluorescein angiography device according to claim 1, characterized in that: The irregular pattern that reduces light reflection is a matte thread.

3. The fundus fluorescein angiography device according to claim 1, characterized in that: A light-absorbing material is sprayed onto the irregular pattern on the conical surface.

4. The fundus fluorescein angiography device according to claim 1, characterized in that: The minimum area of ​​the light-blocking region of the illumination aperture is the minimum area required to eliminate reflected stray light.

5. The fundus fluorescein angiography device according to claim 1, characterized in that: The imaging receiving module is an area array photoelectric converter.

6. A method for fundus fluorescein angiography, characterized in that: This fluorescein angiography method is implemented based on the fundus fluorescein angiography device according to any one of claims 1-5, and specifically includes the following steps: Step 1: Move the fundus fluorescein angiography device to the reset position using a 3D platform; Step 2: Confirm the function to be operated on the fundus fluorescein angiography device. The internal function switching module of the fundus fluorescein angiography device switches the illumination switching component, illumination filter component and imaging filter component to the corresponding positions and keeps their relative positions fixed while rotating along the optical axis. Step 3: Start measurement. The automatic eye-finding module moves the fundus fluorescein angiography device in front of the eye being measured and gradually moves it to the working position. Step 4: The autofocus and fixation module is turned on to stabilize the visual axis direction of the tested eye, and the autofocus makes the image clear; Step 5: If the image is normal, then normal acquisition is performed; if stray light appears in the image, the rotation speed recording module feeds back to the rotation speed modulation module for rotation speed matching adjustment, so that the illumination aperture and function switching module maintain the best matching position and rotate synchronously, and then image acquisition is performed. Step 6: After data acquisition is complete, image analysis is performed, and the device returns to the reset position.

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