CN101336823B - Adaptive Optics Evaluation System for Human Eye Microscopic Field Defects - Google Patents

Abstract

Adaptive optics human eye micro-field defect evaluation system, the light emitted by the beacon enters the pupil of the human eye through the collimator, the first reflector and the beam splitter; the reflected light from the fundus passes through the beam splitter, the beam matching telescope, and the wavefront corrector Reflection, beam matching telescope, second mirror, and beam splitter enter the Hartmann wavefront sensor, and the computer calculates the control voltage according to the measured aberration, and drives the wavefront corrector to correct the aberration of the human eye after amplified by high voltage. After the correction is completed, the computer software will generate the stimulus optotype and display it on the stimulus optotype display device. The subjects will observe the stimulus optotype systematically and make a judgment. By recording the subject’s judgment, the visual field micro-defect situation of the human eye will be assessed. evaluate. The invention adopts the adaptive optics technology to greatly reduce the visual field inspection stimulus redundancy caused by the aberration of the human eye, timely detects early subtle visual field defects caused by diseases, and provides a powerful tool for human eye microscopic visual field evaluation and early diagnosis of related diseases.

Description

Adaptive Optics Evaluation System for Human Eye Microscopic Field Defects

technical field

The invention relates to an adaptive optical human eye micro visual field defect evaluation system, which is an optical instrument used for finely evaluating early micro visual field defect of the human eye.

Background technique

Vision (Visual Field) has a major impact on people's working life as vision. The World Health Organization stipulates that those with visual field less than 100, even if the central vision is normal, are blind. Visual field examination provides important information for ophthalmologists to diagnose and follow up the major blinding eye diseases. Undoubtedly, visual field examination is the basic method for diagnosing and monitoring glaucoma and some other visual and optic nerve diseases. Advanced visual field examination provides the possibility for early diagnosis and condition monitoring of related diseases, and at the same time creates conditions for successful treatment. However, early subtle visual field defects are difficult to diagnose clinically; in the case of glaucoma, by the time visual field defects can be diagnosed using standard automated perimetry, 25% to 30% of ganglion cells have died and many more ganglia may be present The cells have lost function or sensitivity, and the disease hazard has reached a very serious level.

One reason why early visual field defects are difficult to diagnose clinically is that there is "visual redundancy" in the human eye, that is, the response of the human eye to a stimulus visual target is the result of the joint action of multiple neurons or functional cells. Another important reason is that the existing perimetry has "stimulus redundancy", that is, the stimulus optotype covers a certain area in the fundus instead of stimulating single cells. Taking the minimum stimulus visual target of the perimetry currently used clinically as an example, its corresponding viewing angle is about 0.11°. Even without considering the influence of the refractive system of the human eye, the visual target covers about 150 cones in the center of the macular center of the fundus. cells, so that the human eye's response to the visual target is the comprehensive result of the joint response of the cone cells in the area covered by the visual target and all the functional cells directly or indirectly connected to it. If only a part of the functional cells in the stimulus range of the visual target lose function and the rest of the cells function normally, the subject can still make a correct judgment with the help of the response of the normal cells to the stimulus visual target, making it difficult to find the early subtle visual field clinically Defects or central scotomas make it difficult to achieve early diagnosis of glaucoma, optic atrophy and other related diseases.

In order to reduce the impact of "visual redundancy" and "stimulus redundancy" on early subtle visual field defects or central scotoma, new types of visual fields such as short-wavelength automatic perimetry, frequency-doubling perimetry, and high-pass resolution perimetry have been developed in recent years. It is designed to reduce the influence of "visual redundancy" on the visual field test by selectively stimulating short-wave, medium-wave and long-wave cone cells and their corresponding visual pathways, but the stimulus visual target itself is still redundant, so it is also difficult to detect early Subtle visual field defect or central scotoma.

One of the possible ways to solve "stimulus redundancy" is to use the smallest possible stimulus optotype, the limit case of which is to perform single-cell stimulation. However, visual field testing is a psychophysical method, and the stimulus visual target must be projected onto the retina through the human eye's refractive system. The imaging of the stimulus optotype in the fundus is inevitably affected by the diameter of the pupil and the aberration of the human eye. The diameter of the pupil determines the smallest size of the target that can be projected onto the fundus retina, which is limited by the physical diffraction limit of the refractive system. The retinal image resolved by the visual cell (micron level) can be obtained by dilating the pupil; while the human eye image The size of the difference determines the image quality of the stimulus optotype projected to the fundus. The existence of human eye aberrations causes the stimulus optotype to deform and expand in the fundus. Even if a small stimulus optotype is used, redundant stimulation will be formed. Therefore, it is necessary to eliminate the influence of human eye aberrations on the projection of tiny optotypes to the fundus when using tiny stimulus optotypes to evaluate early subtle visual field defects or central scotoma.

In 2006, Walter Makous and D.R.Williams of the Vision Science Center of the University of Rochester in the United States first proposed the use of adaptive optics technology for the detection of subtle visual field defects or central scotomas of the human eye (“Retinal microscotomas revealed with adaptive-optics microflashes”, Walter Makous, Josepb Carroll, et al., Investigative Ophthalmology & Visual Science, 9: 4160-4167, 2006). They used two fixed tiny stimulus optotypes with viewing angles of 7.5' and 0.75', and corrected the aberration of the human eye through an adaptive optics system, so that 55% of the light intensity of the 0.75' stimulus optotype acts on a single cone cell in the fundus, correcting the human eye. The concentration of the stimulus after the eye aberration is corrected is more than 6 times higher than that before the correction, which greatly reduces the redundancy of the stimulus visual target. Using the micro-stimulus visual standard, Walter Makous measured 1 deuteranopia with medium-wave cone defect and 7 normal cone cells (1 deuteranopia, 1 protanomaly, 5 normal color vision) test eyes in the experiment Its visual frequency curve (Frequency-of-Seeing curve). At present, the research of Makous et al. is still in the exploratory stage. Its main purpose is to investigate the effectiveness of adaptive optics technology for micro-field inspection. The research methods still have the following deficiencies:

First, Makous et al. used subjects known to have cone cell defects as test subjects, and their stimulus visual targets were clearly targeted. If the cone cell defect status of the subject is unknown, the single and fixed stimulus optotype may not be able to effectively detect randomly distributed subtle visual field defects or central scotoma.

Second, the position of the stimulus visual target used by Makous et al. is fixed, which is essentially a static visual field inspection method, which can only inspect a limited area;

Third, when Makous et al. measured the visual frequency curve of the test subject, in order to eliminate the influence of the aberration detection beacon light on the test, their adaptive optics system was in a latched state, so they could not monitor the human visual frequency curve during the test. Fluctuation of ocular aberrations.

Contents of the invention

The technical problem to be solved by the present invention is to correct the aberrations of the human eye through adaptive optics technology, and greatly reduce the "stimulus redundancy" in the visual field evaluation by using the small stimulus optotype, so as to effectively evaluate the early subtle visual field defects of the human eye, and found that Early subtle visual field defects caused by diseases such as glaucoma provide a powerful tool for early diagnosis of related diseases.

The technical solution of the present invention is: adaptive optics human eye micro-field defect evaluation system, characterized in that: it consists of a near-infrared beacon, a collimating mirror, a first reflector, a first beam splitter, a human eye, a beam matching telescope, It is composed of wavefront corrector, beam matching telescope, second reflector, second beam splitter, Hartmann wavefront sensor, computer, high-voltage amplifier, third reflector, imaging optical system and stimulus visual target display device. The light emitted by the mark is collimated by the collimator, and reflected into the pupil of the human eye by the first reflector and the first beam splitter; the light reflected by the fundus of the human eye passes through the first beam splitter and the beam matching telescope, and then passes through the wavefront Reflected by the corrector, through the beam matching telescope, to the second reflector, the second reflector reflects the reflected light into the Hartmann wavefront sensor through the second beam splitter, and the Hartmann wavefront sensor sends the acquired spot image to After computer processing to obtain the wave aberration of the human eye, the computer obtains the control voltage of the wavefront corrector through the control software according to the measured wave aberration of the human eye, and drives the wavefront corrector to produce corresponding changes after high-voltage amplification to correct the aberration of the human eye; After the correction of human eye aberration is completed, the computer generates the stimulus visual target through the software, and sends it to the stimulus visual target display device through the video signal to display the stimulus visual target. , the beam matching telescope, the second reflector, the second beam splitter, the third reflector, and the imaging optical system observe the stimulus visual target and make a judgment, and evaluate the micro-defect situation of the human eye field by recording the judgment of the subject.

The Hartmann wavefront sensor is a Hartmann wavefront sensor based on a microprism array, or a Hartmann wavefront sensor based on a microlens array.

The wavefront corrector is a deformable mirror, or a liquid crystal wavefront corrector, or a micromechanical thin film deformable mirror, or a double piezoelectric ceramic deformable mirror.

The stimulus visual mark display device is a CRT display, or a commercial projector, or a color liquid crystal display, or a plasma display, or an electroluminescent display, or an organic light emitting display.

The near-infrared beacon can be a near-infrared laser, or a near-infrared semiconductor laser, or a near-infrared superradiant semiconductor device.

Compared with the prior art, the present invention has the following advantages:

1. The present invention uses adaptive optics technology to correct the dynamic aberrations of the human eye, which greatly reduces the redundancy of visual field inspection stimulation caused by human eye aberrations, thereby timely discovering early subtle visual field defects caused by diseases, and providing a basis for the evaluation and evaluation of human microscopic visual field. Early diagnosis of related diseases provides a powerful tool.

2. The stimulus optotype pattern of the present invention is generated by computer software, and sent to the stimulus optotype display device for display through video signals. The size, quantity, position and intensity of the stimulus optotype can be precisely controlled by the computer. Therefore, the visual field test stimulus design is more flexible, which can effectively detect randomly distributed subtle visual field defects or central scotoma, and can realize dynamic perimetry.

3. The present invention uses near-infrared beacons that are invisible to human eyes, which can avoid the influence of beacon light on visual field evaluation, so that real-time monitoring and correction of human eye aberration can be realized during visual field evaluation, ensuring that the entire testing process is not affected. Effects of human eye aberrations.

Description of drawings

Fig. 1 is a structural schematic diagram of an adaptive optics human eye micro-field defect evaluation system;

Figure 2a is a schematic structural diagram of a Hartmann wavefront sensor based on a microprism array; Figure 2b is a schematic diagram of the working principle of a Hartmann wavefront sensor based on a microprism array;

Figure 3a is a schematic structural diagram of a Hartmann wavefront sensor based on a microlens array; Figure 3b is a schematic diagram of the working principle of a Hartmann wavefront sensor based on a microlens array;

Fig. 4 is two kinds of stimulus visual mark examples;

In the figure: 1 is the near-infrared beacon, 2 is the collimator, 3 is the first reflector, 4 is the first beam splitter, 5 is the human eye, 6 is the beam matching telescope, 7 is the wavefront corrector, 8 is the beam Matching telescope, 9 is the second reflector, 10 is the second beam splitter, 11 is the Hartmann wavefront sensor, 12 is the computer, 13 is the high-voltage amplifier, 14 is the third reflector, 15 is the imaging optical system, 16 is the stimulus visual target display device.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the present invention consists of a near-infrared beacon 1, a collimating mirror 2, a first reflector 3, a first beam splitter 4, a human eye 5, a beam matching telescope 6, a wavefront corrector 7, and a beam matching telescope 8. The second reflection mirror 9, the second beam splitter 10, the Hartmann wavefront sensor 11, the computer 12, the high-voltage amplifier 13, the third reflection mirror 14, the imaging optical system 15 and the stimulus visual mark display device 16 are composed, wherein the near The infrared beacon 1 may be a laser, a semiconductor laser diode, and a superluminescent diode-SLD; the wavefront corrector 7 may be a deformable mirror, a liquid crystal wavefront corrector liquid crystal device, or a micromechanical deformable mirror micro-machined deformable mirror and double piezoelectric ceramic deformable mirror bimorph mirror; the Hartmann wavefront sensor 11 can be a Hartmann wavefront sensor based on a microprism array, or a Hartmann wavefront sensor based on a microlens array; The stimulus visual mark display device 16 can be a CRT display, a commercial projector, a color liquid crystal display, a plasma display, an electroluminescent display, and an organic light-emitting display; the stray light elimination of the human cornea can be eliminated by off-axis lighting; or With polarized light source illumination, the reflected light of the fundus is depolarized, while the scattered light of the cornea is not depolarized. Different polarization states are detected by the analyzer to filter out corneal stray light.

The working process of the adaptive optics human eye micro-field defect evaluation system of this embodiment is as follows: the light emitted by the near-infrared beacon 1 is collimated by the collimator 2, and reflected by the first reflector 3 and the first beam splitter 4 into the human body. The pupil of the eye; the light reflected by the fundus of the human eye 5 passes through the first beam splitter 4 and the beam matching telescope 6, is reflected by the wavefront corrector 7, passes through the beam matching telescope 8, and reaches the second reflector 9, the second reflector 9. The reflected light is reflected into the Hartmann wavefront sensor 11 through the second beam splitter 10, and the Hartmann wavefront sensor 11 sends the acquired spot image to the computer 12 for processing to obtain the wave aberration of the human eye. The wave aberration of the human eye is processed by the control software to obtain the control voltage of the wavefront corrector 7, and after high-voltage amplification 13, the wavefront corrector 7 is driven to produce corresponding changes to correct the aberration of the human eye; after the correction of the aberration of the human eye is completed, the computer The software generates the stimulating optotype, which is sent to the stimulating optotype display device 16 through the video signal to display the stimulating optotype. The human eye 5 passes through the first beam splitter 4, the beam matching telescope 6, the wavefront corrector 7, the beam matching telescope 8, The second reflector 9, the second beam splitter 10, the third reflector 14, and the imaging optical system 15 observe the stimulus visual target and make a judgment, and evaluate the micro-defect condition of the human eye field by recording the judgment of the subject. The present invention uses near-infrared beacons invisible to the human eye, which can avoid the influence of the beacon light on the visual field evaluation, so that real-time monitoring and correction of the human eye aberration can be realized while the visual field evaluation is performed, ensuring that the entire test process is not affected by the human eye. The effect of aberrations.

The Hartmann wavefront sensor 11 may be a Hartmann wavefront sensor based on a microprism array, as shown in Fig. 2a. It consists of a microprism array 11-1 with a two-dimensional zigzag phase grating array structure, a Fourier lens 11-2 and a CCD 11-3 located at the focal plane of the lens. After the incident light beam passes through the microprism array 11-1, the light beams of each sub-aperture produce corresponding phase changes respectively, which are detected by the Fourier lens 11-2 next to it and the CCD 11-3 located on the focal plane of the Fourier lens. Light intensity distribution, the light intensity distribution contains the phase information generated by the two-dimensional zigzag phase grating array 11-1, and the phase changes generated by each sub-aperture are different, thus forming a spot array on the focal plane of the Fourier lens 11-2 , the entire beam aperture is evenly divided. The light spot array generated by standard plane wave incidence is saved in advance as calibration data; when a wavefront with a certain aberration is incident, each local inclined plane wave produces a new additional phase to the two-dimensional zigzag phase grating in its sub-aperture, and the phase change It will be reflected in the spot position shift of the focal plane of the Fourier lens 11-2.

The spot signal received by CCD11-3 can be processed by computer, using the centroid algorithm: Calculate the position of the spot ( _xi , y _i ) by the formula ①, and detect the wave surface error information of the full aperture:

$x_i=\frac{\underset{m=1}{\overset{m}{\mathrm{\Σ}}}\underset{\mathrm{no}=1}{\overset{N}{\mathrm{\Σ}}}{x}_{\mathrm{nm}}{I}_{\mathrm{nm}}}{\underset{m=1}{\overset{m}{\mathrm{\Σ}}}\underset{\mathrm{no}=1}{\overset{N}{\mathrm{\Σ}}}{I}_{\mathrm{nm}}},$ ${\mathrm{the\; y}}_i=\frac{\underset{m=1}{\overset{m}{\mathrm{\Σ}}}\underset{\mathrm{no}=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{the\; y}}_{\mathrm{nm}}{I}_{\mathrm{nm}}}{\underset{m=1}{\overset{m}{\mathrm{\Σ}}}\underset{\mathrm{no}=1}{\overset{N}{\mathrm{\Σ}}}{I}_{\mathrm{nm}}}$ ①

In the formula, m=1～M, n=1～N is the sub-aperture mapped to the corresponding pixel area on the CCD 11-3 photosensitive target surface, and M and N are respectively the lateral and horizontal directions of the sub-aperture mapped to the corresponding area on the photosensitive target surface Vertical pixel number, I _nm is the signal received by the (n, m) pixel on the CCD 11-3 photosensitive target surface, x _nm , y _nm are respectively the x coordinate and the y coordinate of the (n, m) pixel.

Then calculate the wavefront slope g _xi and g _yi of the incident wavefront according to formula ②:

$g_{\mathrm{xi}}=\frac{\mathrm{\&Delta;x}}{\mathrm{\&lambda;f}}=\frac{x_i-x_o}{\mathrm{\&lambda;\; f}},$ $g_{\mathrm{yi}}=\frac{\mathrm{\&Delta;y}}{\mathrm{\&lambda;f}}=\frac{{\mathrm{the\; y}}_i-{\mathrm{the\; y}}_o}{\mathrm{\&lambda;<figure-callout\; id="2"\; label="f"\; filenames="H2008101191284E00011.png"\; state="\{\{state\}\}">f</figure-callout>}}$ ②

In the formula, (x ₀ , y ₀ ) is the reference position of the center of the spot obtained by standard plane wave calibration of the Hartmann sensor; when the Hartmann sensor detects wavefront distortion, the center of the spot is shifted to ( _xi , y _i ), completing the Hartmann sensor The schematic diagram of the signal detection by the Terman wavefront sensor is shown in Figure 2b.

The Hartmann wavefront sensor 11 can also be a Hartmann wavefront sensor based on a microlens array, as shown in Figure 3a, it is made up of a microlens array 11-4 and a photodetector device 11-5, and its working principle is: incident After the beam passes through the microlens array 11-4, a spot array is formed on its focal plane, and the entire beam aperture is evenly divided; the spot array generated by standard plane wave incidence is saved as calibration data. When a wavefront with a certain aberration is incident, the local wavefront tilt on each microlens causes the position of the spot on the focal plane of the microlens array to shift. The schematic diagram of its working principle is shown in Figure 3b. The light spot signal received by the photodetector device 11-5 is processed by a computer in the same manner as the aforementioned Hartmann wavefront sensor based on the microprism array.

The stimulus visual mark display device 16 is a CRT display, or a commercial projector, or a color liquid crystal display, or a plasma display, or an electroluminescent display or an organic light emitting display. Stimulus optotype patterns are generated by computer 12 through software, and are sent to stimulus optotype display device 16 for display through video signals, so the size, quantity, position and intensity of stimulus optotypes can be precisely controlled by computer 12 . Figure 4 is an example of two kinds of stimulus visual marks randomly generated by the software. The left picture shows that four stimulus visual marks are generated at the same time, while the right picture only generates one slightly larger stimulus visual mark. Therefore, visual field test stimulus visual target design is quite flexible, and can achieve dynamic perimetry. In addition, the present invention uses near-infrared beacons that are invisible to human eyes, which can avoid the influence of beacon light on visual field evaluation, so that real-time monitoring and correction of human eye aberrations can be realized while visual field evaluation is performed, ensuring that the entire testing process is not affected. Effects of human eye aberrations.

Claims (10)

1. adaptive optics eyes micro-vision defect evaluation system, it is characterized in that: it is by near-infrared beacon (1), collimating mirror (2), first reflecting mirror (3), first spectroscope (4), Beam matching telescope (6), wave-front corrector (7), Beam matching telescope (8), second reflecting mirror (9), second spectroscope (10), Hartmann wave front sensor (11), computer (12), high-voltage amplifier (13), the 3rd reflecting mirror (14), imaging optical system (15) and stimulation Optotype presenting apparatus (16) are formed, the light that near-infrared beacon (1) sends, by collimating mirror (2) collimation, reflect into human eye (5) pupil through first reflecting mirror (3) and first spectroscope (4); The light of human eye (5) fundus reflex, see through first spectroscope (4) and Beam matching telescope (6), reflect through wave-front corrector (7) again, by Beam matching telescope (8), to second reflecting mirror (9), second reflecting mirror (9) sees through second spectroscope (10) with reflected light and reflects into Hartmann wave front sensor (11), and this Hartmann wave front sensor (11) is delivered to computer (12) with the error signal that records and is processed into aberration of human eye; The aberration of human eye that computer (12) basis records machine control software processes as calculated obtains wave-front corrector (7) control voltage, amplifies (13) rear drive wave-front corrector (7) through high pressure and produces respective change with the correction human eye aberration; After the human eye aberration correction is finished, generate the stimulation sighting target by computer (12) by software, send into stimulation Optotype presenting apparatus (16) through video signal and show the stimulation sighting target, experimenter's eye (5) is observed by first spectroscope (4), Beam matching telescope (6), wave-front corrector (7), Beam matching telescope (8), second reflecting mirror (9), second spectroscope (10), the 3rd reflecting mirror (14) and imaging optical system (15) to stimulate sighting target and makes judgement, by record experimenter's judgement the eyes micro-vision defect situation is estimated.

2. adaptive optics eyes micro-vision defect evaluation system according to claim 1, it is characterized in that: described Hartmann wave front sensor (11) is based on the Hartmann wave front sensor of microprism array, or based on the Hartmann wave front sensor of microlens array.

3. adaptive optics eyes micro-vision defect evaluation system according to claim 1 is characterized in that described wave-front corrector (7) is a deformation reflection mirror.

4. adaptive optics eyes micro-vision defect evaluation system according to claim 1 is characterized in that described wave-front corrector (7) is the liquid crystal wave-front corrector.

5. adaptive optics eyes micro-vision defect evaluation system according to claim 1 is characterized in that described wave-front corrector (7) is a micromechanics deformation of thin membrane mirror.

6. adaptive optics eyes micro-vision defect evaluation system according to claim 1 is characterized in that described wave-front corrector (7) is the double piezoelectric ceramic distorting lens.

7. adaptive optics eyes micro-vision defect evaluation system according to claim 1, it is characterized in that stimulating Optotype presenting apparatus (16) is CRT monitor, or business projector, or colour liquid crystal display device, or plasma scope, or electroluminescent display, or OLED.

8. adaptive optics eyes micro-vision defect evaluation system according to claim 1 is characterized in that near-infrared beacon (1) can be a near infrared laser.

9. adaptive optics eyes micro-vision defect evaluation system according to claim 1 is characterized in that near-infrared beacon (1) can be the near-infrared semiconductor laser.

10. adaptive optics eyes micro-vision defect evaluation system according to claim 1 is characterized in that near-infrared beacon (1) can be a near-infrared superradiance semiconductor device.

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