CN202051688U - Astigmatism objective refractometer based on wave-front aberration - Google Patents

Abstract

The astigmatism objective refractometer based on wavefront aberration is composed of an eye optical system wavefront aberration measuring device based on a Hartmann-Shack sensor, a computer and an output device, and is characterized in that the Hartmann-Shack based The wavefront aberration measuring device of the eye optical system of the sensor includes a beam collimation system composed of a laser diode LD, a microscope objective lens, a pinhole, and a collimator lens, and a beam collimation system composed of a mirror, a polarizing beam splitter, and a beam expander lens. The beam focusing system uses CCD as the image receiving device to receive array spot images, and the image receiving device CCD is connected to the computer. The utility model has the advantages that the astigmatism can be checked objectively, quickly and accurately, and the correction prescription for the astigmatism can be given.

Description

An objective refractometer for astigmatism based on wavefront aberration

technical field

The utility model belongs to the field of medical diagnostic instruments, in particular to an objective optometry instrument for astigmatism based on wavefront aberration. the

Background technique

The detection of astigmatism of the human eye is to provide prescriptions for corrective glasses for patients with incorrect astigmatism. Existing optometry methods for astigmatism are roughly divided into subjective optometry and objective optometry. At present, the internationally recognized conventional optometry equipment is composed of a combination of refractive lens and eye chart. This method is slow in detection speed and requires the subject to make a main statement on the basis of identifying the eye chart. The test results will be affected by the environment. and psychological factors. the

Utility model content

In order to overcome the shortcomings of the existing astigmatism optometry equipment, the utility model provides an objective optometry instrument for astigmatism based on wavefront aberration. the

The technical solution adopted is:

The astigmatism objective refractometer based on wavefront aberration is composed of a wavefront aberration measuring device of the 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 measuring device based on the Hartmann-Shack sensor, the wavefront aberration is expressed by Zernike polynomials. Further calculations result in a prescription for astigmatism correction. the

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

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, a Zernike (Zernike) polynomial to express is obtained. Ocular wavefront aberration data, including tenth order aberrations. The computer calculates by using the wavefront aberration data of the tested eye to obtain the astigmatism correction prescription of the tested eye. the

The formula for calculating astigmatism degree and astigmatism axis from eye wavefront aberration data expressed by Zernike polynomial is:

The utility model has the advantages that it can perform optometry on astigmatism objectively, quickly and accurately, and provide correcting prescriptions for astigmatism. the

Description of drawings

Fig. 1 is a structural representation of the utility model. the

Detailed ways

The laser diode LD1 emits light of 0.78 μm, the beam is focused on the pinhole 3 through the microscope objective lens 2, and then the beam is collimated into a parallel beam by the collimator lens 4, and reflected by the mirror 5 to the polarizing beam splitter 6, After being reflected by the polarizing beam splitter 6, it enters the subject's eye 9 through the beam expander lenses 7 and 8, and falls on the retina 10 to form a very small light spot, which is reflected back by the retina 10 and passes through the polarizing beam splitter 6. and the beam expander lenses 7, 8, 11, 12, and then incident on the small lens array 13. The array spot image formed by the small lens array 13 is received by the CCD 14 , and the CCD 14 is connected with the computer 15 to send the array spot image into the computer 15 . Then the computer 15 processes the array spot image and reconstructs the wavefront to obtain the wavefront aberration data of the eye to be tested. the

The computer 15 uses the wavefront aberration data of the tested eye to perform calculations to obtain the degree of astigmatism and the axis of astigmatism of the tested eye. the

The computer is connected with the output device 16, and outputs the astigmatism degree and astigmatism axial detection results. the

Claims (1)

1. Based on the astigmatism objective optometry instrument of wave front aberration by eye optical system wave-front optical aberration measurement device based on the Shack-Hartmann pick off, computer and outut device constitute, it is characterized in that described eye optical system wave-front optical aberration measurement device based on the Shack-Hartmann pick off comprises by laser diode LD, microcobjective, pin hole, the passing through a collimating system that collimating lens constitutes and by reflecting mirror, polarization beam apparatus, it is image received device that the light beam focusing system that extender lens constitutes adopts CCD, the receiving array light spot image, image received device CCD links to each other with computer.

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