CN101248981A - Visual Optical Analysis System Based on Wavefront Aberration - Google Patents

Abstract

A visual optical analysis system based on wavefront aberration in the field of medical optics technology. In the present invention: the first beam splitter is located between the diaphragm and the cornea, and the emitted light from the Placido disc passes through the second beam splitter and the second beam splitter. The three beamsplitters are projected onto the corneal surface, and the light emitted from the cornea is reflected by the fourth beamsplitter to the corneal topography imaging system. The corneal topography imaging objective lens is located between the first port matching system and the monitoring CCD, and the astigmatism compensation system is located at the first aperture matching system. Between the system and the optical prism, part of the light emitted by the splitter prism is reflected by the second caliber matching system and reaches the target, and the other part is irradiated to the Shaker-Hartmann wavefront sensor, and part of the emitted light by the splitter prism is transmitted to the deformable mirror. A target imaging objective lens is arranged between the five beam splitters and the target, and the Shack-Hartmann wavefront sensor and the deformable mirror are all connected with the computer. The invention not only obtains the data of human eye aberration and corneal surface shape, but also can correct the human eye aberration.

Description

Visual Optical Analysis System Based on Wavefront Aberration

technical field

The invention relates to a system in the technical field of medical optics, in particular to a visual optical analysis system based on wavefront aberration.

Background technique

The Shaker-Hartmann wavefront aberrometer is an objective wavefront analyzer widely used now. The wavefront reflected from the fundus passes through a lens array to form an array of focusing points. If it is an ideal eye system, the reflected parallel wave fronts will produce point arrays with equal intervals and regular distribution after focusing. But for an aberrated eyeball, the individual focus points will deviate. Based on the deviation of each focal point from the ideal position, wavefront aberrations are calculated. For the traditional Shaker-Hartmann wavefront aberrometer, when the aberration is severely deformed, the deviation of the focus point is very large, making it difficult to identify the one-to-one correspondence with the focus point at the ideal position, which makes The calculation of aberration becomes difficult, and this method of detecting wavefront aberration only considers the optical properties of the eyeball, while ignoring the patient's subjective visual response. The patient cannot perceive the measurement results, let alone participate in the measurement process.

Corneal topography is an analysis of the entire corneal surface. It is clinically used to diagnose corneal astigmatism, analyze corneal shape, and display corneal surface shape data in false colors. However, such corneal topography systems for analyzing corneal shape usually do not have the function of analyzing corneal wavefront aberrations.

After searching the literature of the prior art, it is found that the Chinese invention application number is 200410068953.8, and the publication date is January 18, 2006. The patent self-statement is: human eye aberration based on microprism array Shack-Hartmann wavefront sensor And corneal surface measurement system, consisting of pupil or corneal illumination light source, beam splitter, corneal topography imaging objective lens, monitoring CCD (charge-coupled image sensor), beacon light source, beacon light collimation system, aperture control device, mirror, The front group focusing objective lens, the rear group focusing objective lens, the aperture matching system, the Shack-Hartmann wavefront sensor based on the microprism array, the target system, the computer and the additional measuring lens are composed, so that it can realize the measurement of human eye aberration and corneal surface shape, and the switching between the two functions is convenient and easy to operate. It can obtain the low-level and high-level aberration data of the human eye and the corneal surface shape data at one time, which is convenient for understanding the overall aberration of the human eye, corneal aberration and the internal image of the human eye. The characteristics of the difference and the relationship between the three avoid the errors caused by different instruments in the prior art to measure the human eye aberration and corneal aberration respectively, and can provide more accurate and sufficient diagnostic data for clinical medicine. Its shortcoming is that the optical system only measures the low-level and high-level aberrations of the human eye, and cannot reflect the subjective visual response of the subject. It is used in clinical practice where the analysis of the overall aberration of the human eye and each component unit is required.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a visual optical analysis system based on wavefront aberration, which combines the principle of adaptive optics with the Shack-Hartmann wavefront aberration The combination of aberration measurement and corneal topography measurement not only makes it possible to measure various aberrations and corneal topography of the human eye at the same time, it is easy to understand the relationship between the two, but also corrects the aberrations of the human eye, and can Let the subjects give real-time feedback on the objective correction results, so as to correct the vision to the best state.

The present invention is achieved through the following technical solutions, the present invention includes: laser light source, laser collimation beam expander system, aperture, the first beam splitter, the fifth beam splitter, Placido's disc, the second beam splitter, the first beam splitter Three beam splitters, corneal topography imaging objective, first aperture matching system, fourth beam splitter, defocus compensation system, astigmatism compensation system, beam splitting prism, deformable mirror, second aperture matching system, target, target imaging objective, Shaker-Hartmann wavefront sensor, monitoring CCD and computer, where:

The output light of the laser light source reaches the diaphragm through the laser collimation and beam expansion system. The first beam splitter is located between the diaphragm and the cornea, and the output light of the Placido disc is projected to the cornea through the second and third beam splitters. On the surface, part of the light emitted from the cornea is reflected to the corneal topography imaging system through the fourth beam splitter, the corneal topography imaging objective lens is located between the first port matching system and the monitoring CCD, the fourth beam splitter and the defocus compensation system are both arranged at the first Inside the first aperture matching system, the astigmatism compensation system is located between the first aperture matching system and the light prism, and part of the light emitted by the splitter prism reflects and passes through the second aperture matching system, and then reaches the target, and the other part is irradiated to the Shack-Hartmann wave For the front sensor, a part of the output of the beam splitter prism is transmitted to the deformable mirror, and the fifth beam splitter is installed inside the second aperture matching system, and the target imaging objective lens is set between the fifth beam splitter and the target, and the Shack-Hartmann wave front Both the sensor and the deformable mirror are connected to a computer.

The laser collimation and beam expansion system is composed of a spatial filter and a convex lens. The spatial filter is placed at the front focus of the convex lens. After the spatial filter filters the laser light, it becomes parallel light through the convex lens to ensure that the emitted light of the laser light source is parallel. And uniform, and use the diaphragm to take out the central part of the incident light as a thin beam incident on the pupil.

The first aperture matching system is a beam expander system composed of two convex lenses. Since the diameter of the pupil is small, the diameter of the deformable mirror is relatively large, and the focal length of the convex lens close to the pupil is smaller than the focal length of the convex lens close to the deformable mirror. The convex lens is confocal to match the aperture of the pupil exit beam with the deformable mirror.

The second aperture matching system is a beam shrinking system composed of two convex lenses. Since the aperture of the deformable mirror is relatively large and the aperture of the Shack-Hartmann wavefront sensor is relatively small, the focal length of the convex lens close to the deformable mirror Greater than the focal length of the convex lens close to the Shaker-Hartmann wavefront sensor, the two convex lenses are confocal, so as to realize the aperture matching between the output beam of the deformable mirror and the Shaker-Hartmann wavefront sensor.

The defocus compensation system includes two right-angle prisms arranged parallel to each other, the distance between the two right-angle prisms is adjustable, and the defocus compensation is realized by adjusting the distance between the two triangular prisms.

The astigmatism compensation system includes a positive cylinder and a negative cylinder, which are placed orthogonally between the positive cylinder and the negative cylinder, and the angle between the two prisms is adjustable, which is realized by rotating and adjusting the relative angle of the two cylinders Astigmatism compensation.

The Shack-Hartmann wavefront sensor includes: a microlens array, a photoelectric coupling device and a data acquisition card, the focal plane of the microlens array coincides with the surface of the photoelectric coupling device, and the photoelectric coupling device is connected to the computer through the data acquisition card connected.

The computer receives the detection result of the wavefront by the photoelectric coupling device through the photoelectric coupling device, calculates the sub-aperture slope, performs wave front reconstruction and calculates the control voltage according to the control method, and drives the deformable mirror to work after high-voltage amplification to realize the system. Closed loop work.

The deformable mirror refers to a device that can produce surface shape changes under the driving of a control voltage.

In the present invention, the light emitted by Placido's disc is projected onto the surface of the cornea through the first beam splitter, the second beam splitter, and the third beam splitter, and then the cornea of the measured human eye is imaged on the surface of the cornea through the corneal topography imaging objective lens. Monitor the CCD, and obtain the morphological distribution data and graphics of the corneal surface through calculation, and at the same time obtain the wavefront aberration distribution data and graphics of the corneal surface through calculation. The video signal output by the monitoring CCD can be displayed on the computer in real time through the video acquisition card. At the same time, after the light emitted by the laser passes through the laser collimation and beam expansion system, the thin beam intercepted by the diaphragm is incident on the fundus. The wavefront reflected from the fundus is deformed by the refractive medium of the eyeball, and it is transmitted into the fifth beam splitter and divided into two beams, one beam is measured by the Shack-Hartmann wavefront sensor to calculate the wavefront of the eye under test The aberration is transmitted to the computer for storage, the computer calculates the output control voltage, adjusts the surface shape of the deformable mirror to modulate the wavefront of the incident light to compensate for the aberration of the eyeball, until the Shack-Hartmann wavefront sensor detects a uniformly distributed focus Array, this part realizes the objective measurement and correction of eye wavefront aberration; the other wavefront is projected onto the target object after being compensated by the deformable mirror, and the subject can observe the target object and feedback the degree of satisfaction to the computer. Change the surface shape of the deformable mirror for fine-tuning. Therefore, on the basis of objective measurement results, subjective fine-tuning can be realized to determine the eye wavefront aberration distribution for obtaining the best visual effect.

After the laser beam is expanded, the size matches the size of the deformable mirror. The light reflected by the deformable mirror passes through the first aperture matching system and is conjugated with the microlens array on the Shaker-Hartmann wavefront sensor, and the size is also the same as that of the Xiaker-Hartmann wavefront sensor. The size of the microlens array on the Shack-Hartmann wavefront sensor is matched, and the Shack-Hartmann wavefront sensor detects the slope of the wavefront distortion, which is further processed into the phase distribution of the wavefront distortion by calculation. After obtaining the phase distribution of the distorted wavefront, a control signal is generated through a control method. The control signal drives the deformable mirror to deform, correcting aberrations or generating specific aberrations according to system requirements.

The pupil of the eye to be tested is in a conjugate relationship with the deformable mirror through the telephoto system, and the deformable mirror is in a conjugate relationship with the microlens array on the Shaker-Hartmann wavefront sensor through the first aperture matching system, so that the pupil and the Shaker-Hartmann wavefront sensor are in a conjugate relationship. The microlens array on the Hartmann wavefront sensor is also in a conjugate relationship. A monitoring CCD is used to monitor pupil position and size. The defocus compensation system is used to compensate the defocus of the eye under test, and the astigmatism compensation system is used to compensate the astigmatism of the eye under test.

Compared with the prior art, the present invention has the following beneficial effects: the present invention combines the principle of adaptive optics and the Shaker-Hartmann wavefront aberrometer, and can realize the measurement of human eye aberration and corneal topography , to understand the relationship between the two. And on the basis of the existing technology, the correction of human eye aberration is realized. Through defocus and astigmatism compensation, the defocus measurement and correction range of the whole system can reach ±20D, and the astigmatism measurement and correction range can reach ±10D. The testee can give real-time feedback on the objective correction results, so as to correct the vision to the best state. The structure and operation of the system are relatively simple. Through one measurement, not only the data of human eye aberration and corneal surface shape can be obtained, but also the aberration of human eye can be corrected. It is of great significance to help understand the optical characteristics of the human eye cornea, the distribution of wavefront aberrations on the surface of the human eye cornea, and the impact of various higher-order aberrations on human vision. At the same time, it also provides more accurate and effective support for clinical vision optical correction and eye surgery.

Description of drawings

Fig. 1 is a schematic structural diagram of the optical system of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings: this embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following the described embodiment.

As shown in Figure 1, the present embodiment includes: a laser light source 1, a laser collimator and beam expander system 2, an aperture 3, a first beam splitter 4, a fifth beam splitter 5, a Placido disk 6, a second beam splitter Mirror 7, third beam splitter 8, corneal topography imaging objective lens 9, first aperture matching system 10, fourth beam splitter 11, defocus compensation system 12, astigmatism compensation system 13, beam splitting prism 14, deformable mirror 15, second Aperture matching system 16, target object imaging objective lens 17, target object 18, Shack-Hartmann wavefront sensor 19, monitoring CCD20 and computer 21, wherein:

The outgoing light of the laser light source 1 reaches the diaphragm 3 through the laser collimating beam expander system 2, the first beam splitter 4 is located between the diaphragm 3 and the cornea, and the outgoing light of the Placido disk 6 passes through the second beam splitting mirror 7 and The third beam splitter 8 is projected onto the corneal surface, and part of the light emitted by the cornea is reflected to the corneal topography imaging system 9 through the fourth beam splitter 11. The corneal topography imaging objective lens 9 is located between the first aperture matching system 10 and the monitoring CCD 20. The four beam splitters 11 and the defocus compensation system 12 are all arranged inside the first aperture matching system 10, and the astigmatism compensation system 13 is located between the first aperture matching system and the optical prism 14, and part of the light emitted by the beam splitting prism 14 is reflected through the second aperture matching The latter part of the system 16 reaches the target object 18, and the other part is irradiated to the Shaker-Hartmann wavefront sensor 19, and a part of the output of the beam splitting prism 14 is transmitted to the deformable mirror 15, and the second aperture matching system 16 is internally provided with a fifth beam splitter 5 A target imaging objective lens 17 is provided between the fifth beam splitter 5 and the target 18 , and the Shack-Hartmann wavefront sensor 19 and the deformable mirror 15 are connected to the computer 21 .

The laser collimation and beam expansion system 2 includes a spatial filter and a convex lens, the convex lens is located at the rear side of the spatial filter, and the spatial filter is placed at the front focus of the lens to ensure that the outgoing light is parallel light.

The spatial filter has an aperture smaller than or equal to 50 μm.

The first aperture matching system 10 is a beam expander system made up of two convex lenses, wherein the focal length of the convex lens near the eye pupil is smaller than the focal length of the convex lens near the deformable mirror 15, and the two convex lenses are confocal, so as to realize the exit beam of the eye pupil and the The apertures of the deformable mirror 15 are matched.

The focal lengths of the two convex lenses of the first aperture matching system 10 are 120mm and 400mm respectively.

The defocus compensation system 12 includes two right-angle prisms, which are arranged in parallel, and the distance between the two right-angle prisms is adjustable, and the defocus compensation is realized by adjusting the distance between the two triangular prisms.

The defocus compensation system 13 includes two right-angle prisms arranged parallel to each other, the distance between the two right-angle prisms is adjustable, and the defocus compensation is realized by adjusting the distance between the two triangular prisms.

Described second caliber matching system 16, it is the narrowing system that is made up of two convex lenses, wherein the focal length of the convex lens near the deformable mirror 15 is greater than the focal length of the convex lens near the Shaker-Hartmann wavefront sensor 19, both The convex lens is confocal, so as to realize the aperture matching between the output beam of the deformable mirror 15 and the Shaker-Hartmann wavefront sensor 19 .

The focal lengths of the two convex lenses of the second aperture matching system 16 are 150mm and 30mm respectively.

In this embodiment, the corneal illumination light source is a near-infrared light-emitting diode. After the light source is irradiated on the surface of the Placido disc 6, it is projected onto the corneal surface through the second beam splitter 7, and then the corneal topography imaging objective lens 9 will be measured. The cornea of the human eye is imaged on the monitoring CCD20, and the video signal output by the monitoring CCD20 can be displayed in real time on the computer 21 through the video capture card. Adjust the position of the instrument so that the pupil center of the measured human eye is located at the center of the optical axis of the instrument. After the alignment is completed, the video signal of the monitoring CCD20 is input into the computer 21, and the morphological distribution of the corneal surface of the measured eye is obtained by calculation. According to the measured corneal shape distribution, the relative distance between any point on the cornea and the corresponding point on the arbitrarily set reference surface can be calculated, and this relative distance is multiplied by the corneal refractive index. In this embodiment, the corneal refractive index n is 1.376, which can be The wavefront aberration distribution of the corneal surface was obtained.

At the same time, after the light emitted by the laser light source 1 is collimated and expanded, the thin light beam intercepted by the diaphragm 3 enters the fundus. The wavefront reflected from the fundus is deformed by the refractive medium of the eyeball, the beam is expanded by the first aperture matching system 10, and the defocus compensation system 12 and astigmatism compensation system 13 are adjusted to compensate for defocus and astigmatism. The light is irradiated on the deformable mirror 15, and the reflected light of the deformable mirror 15 is reflected by the dichroic prism 14, and then passed into the fifth dichroic mirror 5 and then divided into two beams, one beam is measured by the Shack-Hartmann wavefront sensor 19 and stored and transmitted to the computer 21, and then the computer 21 sends a signal to adjust the deformable mirror 15 to compensate the aberration of the eyeball until the Shack-Hartmann wavefront sensor 19 detects a uniformly distributed focusing array, and this part realizes objective measurement and correction; the other beam After the wavefront is compensated by the deformable 15 micromirror array, it is projected onto the target object 18 (such as an eye chart), and the subject can observe the target object 18 and feed back the satisfaction degree to the computer 21. Above, fine-tuning is performed by changing the distribution of the micromirror array in the deformable mirror 15, and finally the aberration is calculated according to the change of the distribution of the micromirror array in the deformable mirror 15, so as to realize the subjective wavefront aberration when obtaining the best visual effect measurement and correction. The aberrations of other parts of the eye can be obtained by subtracting the obtained ocular aberrations and corneal aberrations, and the analysis of the wavefront aberrations of different parts of the eye can be realized.

This embodiment can realize the measurement of human eye aberration and corneal topography, and realize the correction of human eye aberration, and the subject can give real-time feedback on the objective correction result, so as to correct the vision to the best state . Through defocus and astigmatism compensation, the defocus measurement and correction range of the whole system can reach ±20D, and the astigmatism measurement and correction range can reach ±10D. The structure and operation of this embodiment are relatively simple, and not only the data of human eye aberration and corneal surface shape can be obtained through one measurement, but also the human eye aberration can be corrected. It is of great significance to help understand the optical characteristics of the human eye cornea, the distribution of wavefront aberrations on the surface of the human eye cornea, and the impact of various higher-order aberrations on human vision.

Claims (7)

1, a kind of visual optics analysis system based on wave front aberration, comprise: LASER Light Source, laser alignment beam-expanding system, first spectroscope, the 5th spectroscope, second spectroscope, the 3rd spectroscope, corneal topography image-forming objective lens, the first bore matching system, the 4th spectroscope, Amici prism, Shack-Hartmann wave front sensor, object, supervision CCD and computer, it is characterized in that, also comprise: diaphragm, placido plate, defocusing compensation system, astigmatism compensation system, distorting lens, object image-forming objective lens, the second bore matching system, wherein:

The emergent light of LASER Light Source arrives diaphragm through the laser alignment beam-expanding system, first spectroscope is between diaphragm and cornea, the emergent light of placido plate is projected to anterior corneal surface through second spectroscope and the 3rd spectroscope, a part of light of cornea outgoing reflexes to the corneal topography imaging system via the 4th spectroscope, the corneal topography image-forming objective lens is between first mouthful of matching system and supervision CCD, the 4th spectroscope and defocusing compensation system all are arranged at the first bore matching system inside, the astigmatism compensation system is between the first bore matching system and light prism, a part of luminous reflectance of Amici prism outgoing through the second bore matching system after a part arrive object, another part shines Shack-Hartmann wave front sensor, the part of Amici prism outgoing is transferred to distorting lens, the second bore matching system inside is provided with the 5th spectroscope, be provided with the object image-forming objective lens between the 5th spectroscope and the object, Shack-Hartmann wave front sensor all links to each other with computer with distorting lens.

2, the visual optics analysis system based on wave front aberration according to claim 1 is characterized in that, described laser alignment beam-expanding system is made up of a spatial filter and a convex lens, and spatial filter places convex lens front focus place.

3, the visual optics analysis system based on wave front aberration according to claim 1, it is characterized in that, the described first bore matching system, it is the beam-expanding system of being made up of two convex lenss, wherein the focal length of convex lens of close eye pupil is less than the focal length of convex lens near distorting lens, and two convex lenss are confocal.

4, the visual optics analysis system based on wave front aberration according to claim 1, it is characterized in that, the described second bore matching system, its beam system that contracts for forming by two convex lenss, wherein the focal length of the convex lens of close distorting lens is greater than the focal length of the convex lens of close Shack-Hartmann wave front sensor, and two convex lenss are confocal.

5, the visual optics analysis system based on wave front aberration according to claim 1 is characterized in that, described defocusing compensation system comprises two corner cube prisms, parallel placement between two corner cube prisms.

6, the visual optics analysis system based on wave front aberration according to claim 1 is characterized in that, described astigmatism compensation system comprises positive column mirror and negative post mirror, and quadrature is placed between positive column mirror and the negative post mirror.

7, the visual optics analysis system based on wave front aberration according to claim 1, it is characterized in that, described Shack-Hartmann wave front sensor, comprise: microlens array, photoelectric coupled device and data collecting card, the focal plane of microlens array overlaps with the surface of photoelectric coupled device, and photoelectric coupled device links to each other with computer by data collecting card.