CN201492404U - Contrast Sensitivity Detector Based on Wavefront Aberration - Google Patents

Abstract

The utility model belongs to the field of medical diagnostic instruments. The utility model is based on the contrast sensitivity detector of wavefront aberration and comprises the eye optical system wavefront aberration measuring device based on the Hartmann-Shack sensor; a connected computer; an output device connected with the computer, used to output contrast sensitivity test results. The specific sensitivity tester can objectively, quickly and accurately measure the contrast sensitivity of the visual system, and provide the test result.

Description

Contrast Sensitivity Detector Based on Wavefront Aberration

technical field

The invention belongs to the field of medical diagnostic equipment.

Background technique

Eyes are the most important organ for human beings to obtain external information. About 95% of human information comes from vision when they recognize the world around them. Visual function detection and visual diagnosis have always been a major event involving almost all public health. The range of visual functions includes shape perception, stereo vision, light perception, field of vision and color vision. The most important function of the visual system is form perception, and usually visual acuity is used as a clinical evaluation index for form perception function. However, simply using visual acuity to evaluate the shape perception function of the human eye has limitations, and cannot fully and accurately reflect the characteristics of the shape perception function of the human eye. Visual acuity only reflects the highest contrast at the macula and the resolution of small objects. However, vision is far more complex, and it is related to many factors such as contrast, adaptation, movement, and color. Some diseases such as glaucoma, retinitis pigmentosa, etc., even if the central vision is still good or normal, but when the contrast of the target or object is reduced, it interferes with vision, manifested as a decline in form perception function. Since the 1990s, people have noticed more and more that in visual measurement, in addition to central vision, the change of contrast has unique significance for the formation of vision. Therefore, the measurement of object contrast discrimination ability has become a kind of A new and more comprehensive evaluation parameter of form perception function, that is, contrast sensitivity. Combining visual acuity and contrast sensitivity as an evaluation index of form perception function can not only reflect the characteristics of human eye form function more comprehensively and accurately, give more information about visual function, but also reflect the optical properties of human eyes. Systemic defects and defects of the retina and optic nerve.

The current test method for contrast sensitivity is graphic thresholding. This method requires the subject to recognize the grating graphics of different spatial frequencies and different contrasts one by one, and the detection speed is slow. 32 different grating graphics allow the subject to be recognized one by one; in addition, this method is subjective, it depends on the main statement of the subject, and the test results are greatly affected by environmental and psychological factors.

Contents of the invention

In order to overcome the shortcomings of the existing test methods for contrast sensitivity, the present invention provides a contrast sensitivity detector based on wavefront aberration. The contrast sensitivity detector overcomes the shortcomings of the traditional contrast sensitivity detection method, and can measure the contrast sensitivity objectively, quickly and accurately.

The scheme that the utility model solves its technical problem adopts is:

The contrast sensitivity detector based on wavefront aberration is composed of a wavefront aberration measuring device of an eye optical system based on a Hartmann-Shack sensor, a computer and an output device. According to the eye wavefront aberration data detected by the eye optical system wavefront aberration measurement device based on the Hartmann-Shack sensor, the autocorrelation calculation of the generalized pupil function is performed to obtain the optical modulation transfer function MTF of the eye optical system. The optical modulation transfer function MTF of the eye optical system and the AIM curve of the retinal modulation degree can be further calculated to obtain the contrast sensitivity.

The wavefront aberration measuring device of the eye optical system based on the Hartmann-Shack sensor uses a laser diode LD as the light source, a beam collimation system composed of a microscope objective lens, a pinhole, and a collimator lens, and a reflector, a polarizer, and a beam collimator. The beam focusing system composed of beam splitter and beam expander lens collimates and focuses the beam emitted by the light source LD onto the retina; the small lens array and CCD constitute a Hartmann-Shack sensor, and the small lens array will reflect the light beam reflected by the retina The wavefront of the small lens array is divided into several sub-wavefronts, and all the sub-wavefronts form an array spot image. The center distance of the lenslets of the small lens array is less than 0.3mm. Aberrations provide resolution; CCD is used as the image receiving device to receive array spot images.

The image receiving device CCD is connected to the computer, and the received array spot image is input into the computer, compared with the standard image pre-stored in the computer, and through image processing and wavefront reconstruction, the wavefront aberration data of the eye under test and including Ten-order aberrations including defocus and astigmatism. The computer uses the wavefront aberration data of the tested eye to carry out the autocorrelation calculation of the generalized pupil function to obtain the optical modulation transfer function (MTF) of the eye optical system, and the optical modulation transfer function (MTF) and the retinal spatial image modulation degree AIM curve, further Calculate, and then get the contrast sensitivity of the visual system.

The computer is connected with the output device to output the contrast sensitivity detection result of the visual system.

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Description of drawings

Accompanying drawing 1 is the structural principle diagram of the contrast sensitivity detector based on wavefront aberration of the present invention.

Detailed ways

As shown in Figure 1, the laser diode LD (1) emits light of 0.78 μm, the light beam is focused on the pinhole (3) by the microscope objective lens (2), and then the light beam is collimated by the collimator lens (4) into The parallel light beam is reflected by the mirror (5) to the polarizing beam splitter (6), and after being reflected by the polarizing beam splitter (6), it enters the eye (9) through the beam expander lens (7, 8) and lands on the retina (10) forms an extremely small spot of light, which is reflected back by the retina (10), passes through the polarizing beam splitter (6) and the beam expander lens (7, 8, 11, 12), and then enters the small lens On the array [13]. The array spot image that lenslet array (13) forms is received by CCD (14), and CCD (14) is connected with computer (15), and array spot image is sent in the computer (15). Then the computer [15] processed the array spot image and reconstructed the wavefront to obtain the wavefront aberration data of the eye under test.

The computer (15) utilizes the wavefront aberration data of the eye to be tested to carry out the autocorrelation calculation of the generalized pupil function, and obtains the optical modulation transfer function MTF of the eye optical system, and compares the optical modulation transfer function MTF and the retinal spatial image modulation degree ( AIM) curve, further calculation, and then get the contrast sensitivity of the visual system.

The computer is connected with the output device (16) to output the contrast sensitivity detection result of the visual system.

Claims (5)

1. contrast sensitivity detector based on wave front aberration, it is characterized in that: described eyesight detecting instrument based on wave front aberration comprises the optics of the eye system wave-front optical aberration measurement device based on the Shack-Hartmann pick off; One computer that links to each other; One outut device that links to each other with described computer.

2. the contrast sensitivity detector based on wave front aberration as claimed in claim 1 is characterized in that: described optics of the eye system wave-front optical aberration measurement device based on the Shack-Hartmann pick off comprises that one is used to produce the light supply apparatus by the point source image of retinal reflex; One is used for the point source image of described retinal reflex is converted to the lenslet array of array light spot image; One is used to receive the ccd image receiving system of described array light spot image.

3. the contrast sensitivity detector based on wave front aberration as claimed in claim 1 is characterized in that: described is light source LD, microcobjective, pin hole, collimating lens, reflecting mirror, polarization beam apparatus, extender lens sequence arrangement based on the light supply apparatus in the optics of the eye system wave-front optical aberration measurement device of Shack-Hartmann pick off.

4. the contrast sensitivity detector based on wave front aberration as claimed in claim 1 is characterized in that: described lenslet center distance based on lenslet array in the optics of the eye system wave-front optical aberration measurement device of Shack-Hartmann pick off is less than 0.3mm.

5. the contrast sensitivity detector based on wave front aberration as claimed in claim 1 is characterized in that: in the described optics of the eye system wave-front optical aberration measurement device based on the Shack-Hartmann pick off, the ccd image receiving system is connected with described computer.

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