A fully automatic phoropter and a method of optometry

Abstract

The application provides a full-automatic optometry topographic chart instrument, comprising an imaging system and a control processing system, the imaging system comprises an imaging assembly, an illumination device and a shooting device, the light exit side of the illumination device is provided with a projection objective, the light exit side of the projection objective is provided with a digital micromirror device or a transmission type calibration plate with a projection pattern, and the projection pattern is used for assisting qualitative and quantitative analysis of the refractive degree of the human eye; the control processing system comprises a data processing module for receiving fundus images and calculating a generated topographic chart and an output display module for displaying the topographic chart. The application also provides an optometry method using the full-automatic optometry topographic chart instrument. The full-automatic optometry topographic chart instrument and the optometry method provided by the application have simple equipment structure, low cost, complete detection parameters, and can obtain the ametropia condition of the human eye through the change of the projection pattern characteristics, and then obtain the optometry topographic chart through image processing.

Description

Technical Field

[0001] This invention relates to a topographic map instrument and a refraction method, and more particularly to a fully automated refraction topographic map instrument and a refraction method for ophthalmic examination. Background Technology

[0002] Refraction testing is a common procedure in clinical ophthalmology clinics, typically used to detect refractive errors such as myopia, hyperopia, and astigmatism. According to the World Health Organization, my country has the largest population of people with refractive errors in the world. Refractive errors not only affect individual visual health but also impact the training of a large number of professionals, including those involved in military recruitment, pilot training, navigation, firefighting, and criminal investigation. Therefore, the detection, evaluation, and effective prevention of refractive errors are crucial.

[0003] In the evaluation of refractive errors, the refractive power of the central field of vision is one of the most important parameters for assessing human visual acuity. Most existing visual acuity measurement devices primarily measure the refractive power of the central field of vision. Studies have shown that the refractive power of the peripheral field of vision influences the development trend of visual acuity. However, the exact magnitude of this peripheral refractive power and its specific impact on visual acuity remain unclear. This is because no existing commercial optometry product offers a convenient and reliable method for continuous, high-density measurement of the peripheral refractive state of the retina. In existing technology (CN202011088042.7), refractive topography primarily works by detecting different defocus positions when light of different wavelengths converges on the retina and using defocus compensation to simulate and calculate the refractive topography of the retina. However, such refractive topography instruments require multispectral light sources, resulting in high cost and complex structure. Summary of the Invention

[0004] The purpose of this invention is to overcome the existing defects and provide a fully automatic optometric topographic map instrument and optometric method, solving the problems of limited detection parameters, high cost, and complex structure of current optometric equipment.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A fully automatic optometric topographic mapper includes an imaging system and a control and processing system. The imaging system includes an imaging component, an illumination device, and an imaging device. A projection lens is provided on the light-emitting side of the illumination device, and a digital micromirror device or a transmissive calibration plate with a projection pattern is provided on the light-emitting side of the projection lens. The projection pattern is used to assist in the qualitative and quantitative analysis of the refractive power of the human eye. The projection pattern has the characteristics of clear outline, sharp edges, regular arrangement, and easy calculation and analysis of pattern changes. The control and processing system includes a data processing module for receiving fundus images and calculating and generating topographic maps, and an output display module for displaying the topographic maps.

[0007] Furthermore, the imaging assembly includes a retinal objective for the first imaging, an image-rotating mirror group for the second imaging, and a collimating mirror group for the third imaging. The imaging device is used to capture the third imaging. A first polarizer is disposed between the retinal objective and the image-rotating mirror group. The optical path of the first polarizer is parallel to and relatively independent of the optical path of the projection objective.

[0008] Furthermore, the control processing system is connected to a drive device, which can control the movement of the rotating mirror group or the collimating mirror group to adjust the relative positions of the rotating mirror group and the collimating mirror group.

[0009] Furthermore, the driving device is a stepper motor, which is connected to the collimating lens assembly.

[0010] Furthermore, the lighting device includes a light source and a driver, the driver being used to adjust the output brightness of the light source, and a second polarizer being disposed between the light source and the projection lens.

[0011] Furthermore, the control processing system is connected to the driver via a drive circuit.

[0012] Furthermore, the projected pattern is a black and white checkerboard pattern.

[0013] Furthermore, the material of the transmissive calibration plate is glass or plastic.

[0014] A refraction method using the aforementioned fully automated refractometer includes the following steps:

[0015] S1. The control and processing system controls the driver through the drive circuit to keep the light source constantly lit at a low brightness. The light passes through the second polarizer and the projection lens to project the projection pattern onto the human eye's retina.

[0016] S2. The control and processing system adjusts the relative positions of the image-rotating lens group and the collimating lens group to focus on the clarity of the fundus image. After focusing, exposure begins, and the brightness of the light source is rapidly increased to obtain a clear fundus image with a projected pattern. Then, the image is saved and the brightness of the light source is reduced to a lower level to protect the human eye.

[0017] S3. The data processing module uses a fundus image with a projection pattern that is in normal refractive state as a reference to calculate the changes in the projection pattern in the obtained fundus image, thereby obtaining the corresponding refractive error of the human eye, and then obtaining the refraction parameters and generating a refraction topography map.

[0018] Further, in step S2, a fundus image is captured at the position where the center of the projected pattern is most clearly imaged. Then, the stepper motor is controlled to move in two directions, front and back, and a fundus image is captured for each rotation angle of the motor. The front and back directions correspond to myopia defocus and hyperopia defocus, respectively, and several fundus images are captured in each direction.

[0019] This invention discloses a fully automatic optometric topographic map instrument and optometric method. The equipment has a simple structure, low cost, and complete detection parameters. It utilizes the principle that different refractive errors of the human eye will cause different degrees of changes in the image details after the projected pattern is reflected by the retina and imaged by the fundus imaging module. By analyzing the changes in the features of the projected pattern, the refractive error of the human eye can be determined. Then, after image processing, an optometric topographic map can be obtained. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a schematic diagram of the optical path structure when the fully automatic optometric topographic map instrument is in use;

[0022] Figure 2 It is a schematic diagram of a black and white checkerboard pattern;

[0023] Figure 3 This is a schematic diagram of an alternative projection pattern;

[0024] Figure 4 This is a flowchart illustrating the optometry process;

[0025] Figure 5 This is a schematic diagram of a fundus image that incorporates a projection pattern in an optometry method. Detailed Implementation

[0026] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] A fully automatic optometric topographic mapper includes an imaging system and a control and processing system. The imaging system includes an imaging component, an illumination device, and an imaging device. A projection lens 1 is provided on the light-emitting side of the illumination device, and a transmissive calibration plate 2 with a projection pattern is provided on the light-emitting side of the projection lens 1. The projection pattern is used to assist in the qualitative and quantitative analysis of the refractive power of the human eye. The projection pattern has the characteristics of clear outline, sharp edges, regular arrangement, and easy calculation and analysis of pattern changes. The control and processing system includes a data processing module 3 for receiving fundus images and calculating and generating topographic maps, and an output display module 4 for displaying the topographic maps.

[0028] A transmissive calibration plate with a projected pattern can be replaced with a digital micromirror device (DMD), each containing millions of independently controlled micromirrors (built on corresponding CMOS memory cells). During operation, the DMD's controller loads a "1" or a "0" for each basic memory cell, followed by a mirror reset pulse. This causes each micromirror to electrostatically deviate by approximately one angle, reaching a corresponding + / -12° state. The deviation angles of these two effective states are repeatable, as they are physically stopped by the resistance of two spring-loaded pins. In the projection system, the +12° state corresponds to an "on" pixel, and the -12° state corresponds to an "off" pixel. The projected pattern is created by programming the on / off duty cycle of each mirror. The process of generating the projected pattern using the DMD can be implemented by a control processing system that controls the DMD's controller.

[0029] The imaging system is a high-resolution fundus camera optical system that meets the requirements for clear imaging of the human retina over a large field of view. The imaging components include a retinal objective lens 5 for the first imaging 105, an image-rotating mirror group 6 for the second imaging 106, and a collimating mirror group 7 for the third imaging. The imaging device is used to capture the third image. A first polarizer 8 is disposed between the retinal objective lens 5 and the image-rotating mirror group 6. The optical path of the first polarizer 8 is parallel to and relatively independent of the optical path of the projection objective lens 1.

[0030] Figure 1 This is a schematic diagram of the optical path structure when the present invention is used, where 101 is the human eye, 102 is the retina, 103 is the eyeball, and 104 is the pupil. The specific optical path principle is as follows: The light source emits monochromatic light, which passes sequentially through the first polarizer, the projection lens, the transmission calibration plate with the projection pattern, the retinal lens, the pupil, and the eyeball before reaching the retina; the light undergoes diffuse reflection on the retina, and the reflected light passes sequentially through the eyeball, the pupil, and the retinal lens to form the first image; the light then passes through the second polarizer and enters the image-transferring lens group to form the second image; and finally passes through the collimating lens group to form the third image.

[0031] The control and processing system is connected to a drive device, which is a stepper motor. The stepper motor is connected to the collimating lens group 7 and can control the movement of the collimating lens group 7 to adjust the relative position of the image rotating mirror group 6 and the collimating lens group 7, thereby completing defocus compensation.

[0032] The illumination device includes a light source 9 and a driver. The driver is used to adjust the brightness of the light emitted by the light source 9. A second polarizer 10 is disposed between the light source 9 and the projection lens 1. The light source serves as both the illumination source for the fundus and the illumination source for the projection lens. The light source employs a fully apochromatic illumination technology with a reflector bowl, which is an improvement on the Köhler illumination system. This technology can eliminate chromatic aberration, enhance light reproduction, and thus improve resolution. At the same time, the illumination is uniform and highly efficient, allowing the projected pattern to receive uniform and sufficiently bright illumination, ensuring high-resolution projection of the pattern without glare.

[0033] The control and processing system is connected to the driver through a drive circuit, thereby realizing the automatic adjustment of the light source brightness.

[0034] The projected pattern is a black and white checkerboard pattern, such as... Figure 2 As shown, the projection pattern consists of n×n small black and white squares, each with a side length of C / n (mm), where C is the diameter of the human retina. Other projection patterns can include concentric rings, diamond grids, orderly arranged patterns, or circles composed of alternating black and white sectors, such as... Figure 3 As shown.

[0035] The transmissive calibration plate 2 is made of glass or plastic.

[0036] Data processing module 3 employs a high-performance microcomputer data processing center to complete various types of data processing, including feedback data required by the control processing system and optometry parameters required by the output display module.

[0037] like Figure 4 As shown, a refraction method using the aforementioned fully automated refractometer includes the following steps:

[0038] S1. The control and processing system controls the driver through the drive circuit to keep the light source constantly lit at a low brightness. The light passes through the second polarizer and the projection lens to project the projection pattern onto the human eye's retina.

[0039] S2. The control and processing system adjusts the relative positions of the image-shifting lens group and the collimating lens group to focus on the clarity of the fundus image. After focusing, exposure begins, and the brightness of the light source is rapidly increased to obtain a clear fundus image A with a projected pattern (e.g., ...). Figure 5 As shown), focus on the position that makes the center of the projected pattern clearest and take a fundus image A. Then, control the stepper motor to move in the front and back directions through the control processing system. Take a fundus image A for each rotation of the motor. The front and back directions correspond to myopia defocus and hyperopia defocus respectively. Take 10 fundus images A in each direction. Then save these images and reduce the brightness of the light source to a lower brightness state to protect the human eye.

[0040] S3. The data processing module uses a fundus image with a projection pattern that is in normal refractive state as a reference to calculate the changes in the projection pattern in the obtained fundus image A, thereby obtaining the corresponding refractive error of the human eye, and then obtaining the refraction parameters and generating a refraction topography map.

[0041] Due to the presence of defocus, the detailed features of the projected pattern on each fundus image will change in accordance with the defocus situation. By analyzing and calculating this change through image processing algorithms, the magnitude and direction of the defocus can be determined, enabling more accurate acquisition of the refraction parameters and refraction topography of the human eye.

[0042] This invention discloses a fully automatic optometric topographic map instrument and optometric method. The equipment has a simple structure, low cost, and complete detection parameters. It utilizes the principle that different refractive errors of the human eye will cause different degrees of changes in the image details after the projected pattern is reflected by the retina and imaged by the fundus imaging module. By analyzing the changes in the features of the projected pattern, the refractive error of the human eye can be determined. Then, after image processing, an optometric topographic map can be obtained.

[0043] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fully automatic optometric topographic mapper, characterized in that: Including imaging systems and control and processing systems, The imaging system includes an imaging component, an illumination device, and an imaging device. The illumination device has a projection lens on its light-emitting side, and the projection lens has a digital micromirror device or a transmission calibration plate with a projection pattern on its light-emitting side. The projection pattern is used to assist in the qualitative and quantitative analysis of the refractive power of the human eye. The projection pattern has the characteristics of clear outline, sharp edges, regular arrangement, and easy calculation and analysis of pattern changes. The control and processing system includes a data processing module for receiving fundus images and calculating and generating topographic maps, and an output display module for displaying the topographic maps. The imaging components include a retinal objective for the first imaging, an image-rotating lens group for the second imaging, and a collimating lens group for the third imaging. The imaging device is used to capture the third imaging. A first polarizer is disposed between the retinal objective and the image-rotating lens group, and the optical path of the first polarizer is parallel to and relatively independent of the optical path of the projection objective. The control and processing system is connected to a driving device, which can control the movement of the image-rotating lens group or the collimating lens group to adjust their relative positions. The driving device is a stepper motor, which is connected to the collimating lens group. The illumination device includes a light source and a driver, which is used to adjust the brightness of the light source. A second polarizer is disposed between the light source and the projection objective. The control and processing system is connected to the driver through a driving circuit. The projection pattern is a black and white checkerboard pattern. The transmissive calibration plate is made of glass or plastic. The refraction method of this fully automated refractometer includes the following steps: S1. The control and processing system controls the driver through the drive circuit to keep the light source constantly lit at a low brightness. The light passes through the second polarizer and the projection lens to project the projection pattern onto the human eye's retina. S2. The control and processing system adjusts the relative positions of the image-rotating lens group and the collimating lens group to focus on the clarity of the fundus image. After focusing, exposure begins, and the brightness of the light source is rapidly increased to obtain a clear fundus image with a projected pattern. Then, the image is saved and the brightness of the light source is reduced to a lower level to protect the human eye. S3. The data processing module uses a fundus image with a projection pattern that is in normal refractive state as a reference to calculate the changes in the projection pattern in the obtained fundus image, thereby obtaining the corresponding refractive error of the human eye, and then obtaining the refraction parameters and generating a refraction topography map. In step S2, a fundus image is captured at the position that makes the center of the projected pattern clearest. Then, the stepper motor is controlled by the control processing system to move in two directions, front and back. A fundus image is captured for each rotation angle of the motor. The front and back directions correspond to myopia defocus and hyperopia defocus, respectively. Several fundus images are captured in each direction.

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