CN118592886A - A VR measurement system and method for detecting human vision at different distances - Google Patents

Abstract

The invention belongs to the technical field of vision detection, and particularly discloses a VR measuring system and a VR measuring method for detecting vision of human eyes at different distances, wherein the VR measuring system comprises a VR optical system and a Badal optical system, and the VR measuring system is combined with a VR vision detector by utilizing the characteristics of Badal optical imaging angle magnification invariance and constant vision angle resolution, so that the detection of specific distances of far vision and near vision can be realized, and the detection distance is 5-25 cm; the system can improve the applicability of the detection device data to different patients, has the advantages of simpler operation, short detection time, large measurement refractive range and lower detection cost, and most importantly, the subjective refractive state data is sufficient, so that the detection of refractive coefficients, the maximum adjustment range of crystalline lenses, near vision and far vision and the function of autonomous lens allocation can be realized.

Description

A VR measurement system and method for detecting human vision at different distances

Technical Field

The present invention relates to the technical field of vision detection, and in particular to a VR measurement system and method for detecting human vision at different distances.

Background Art

As people's requirements for visual quality increase, restoring far and near vision functions is the goal pursued by refractive surgery and cataract surgery. After lens implantation, the patient's postoperative vision is usually evaluated, and the changes in far, medium and near distance vision and their changing trends are discussed respectively. Visual acuity or visual resolution (i.e., the ability of the eye to distinguish the minimum distance between two external object points) is usually expressed by visual angle (i.e., the angle between the two ends of the object and the first node of the eye). The smaller the visual angle, the better the vision. The reciprocal of the visual angle is often used to express visual acuity. Usually, the sight mark is formulated based on the design principle of the letter vision chart designed by Snellen in 1862. It is designed according to the minimum resolution angle of 1′ visual angle, and 1′ visual angle is used as the standard for normal vision. The measurement standard of near and far vision is based on this standard. Using the 5-point recording method designed by Professor Miao Tianrong, 5m, 3m, 60cm, and 40cm logarithmic vision charts are designed to detect the near and far vision of the human eye. Far and near vision is one of the important contents of visual function and refractive function. Under normal circumstances, the near vision and far vision of the human eye are generally not much different. However, in the case of myopic refractive error, the far vision is often not as good as the near vision, resulting in differences in viewing angles when the human eye observes objects at different distances. The excellence of vision correction cannot be judged simply by optometry or a 5m vision chart, but also requires the combined use of far and near vision data to judge.

The existing methods for measuring far and near vision include the standard logarithmic vision chart based on the 5-point recording method, the near vision chart, the intelligent vision detection system based on VR glasses, the projection vision chart, etc. These vision charts can only detect far and near vision at a specified distance (5m, 3m, 40cm, etc.), and cannot obtain the closest and farthest distances that the human eye can see at a 1′ viewing angle, and perform specific distance detection, thereby quantifying the specific standards of near and far vision. By observing the specific visible distances of near and far vision, quantitative analysis of optometry diseases such as artificial lens correction, presbyopia, amblyopia, and abnormal visual function can be performed through scientific data.

At present, common correction effect analysis devices are mainly based on refractive optometry, naked eye distance vision test (standard logarithmic eye chart, test distance 5m), in addition to near vision test (standard logarithmic eye chart, test distance 33cm), binocular vision function test, including adjustment test (adjustment amplitude, adjustment sensitivity, positive and negative relative adjustment), vergence function test (horizontal fusional vergence, convergence near point), AC/A test, eye position test, etc. It is mainly to check the eyes in all directions, check and analyze the data in different directions for abnormalities. Not to mention the long time, the detection steps are very cumbersome, easy to cause eye fatigue and affect the accuracy of the test, and it must be analyzed by relevant doctors, with many re-examinations and long cycles.

At present, most of the common devices for detecting near and far vision use a vision chart test device to test naked eye far vision (standard logarithmic vision chart, test distance 5m), near vision (standard logarithmic near vision chart, test distance 33cm), and perform far and near vision tests after correcting vision. The principle is to use a vision chart to test vision at standard far and near distances, so as to understand the changes in vision, analyze the nature and degree of refractive error, improve the speed and accuracy of optometry, and obtain the only optimal prescription for glasses. However, the existing vision correction effect analysis test can only obtain vision of 5m and 33cm, and cannot obtain quantitative detection at different distances, and cannot obtain the closest and farthest distances that the human eye can see at a 1′ viewing angle. The data collected by the vision correction effect analysis instrument is information from different parts, and for people with amblyopia, pseudomyopia, and mild myopia who have poor early treatment effects, slight changes in different parts cannot fully detect the correction effect, and the applicability is reduced.

Most of the common subjective optometry at this stage uses an adjustable vision test device. The principle is that when wearing the test device, different types of defocus compensation sheets or astigmatism compensation sheets can be added to the device, and then the clarity of the eye chart can be observed by the human eye to judge the refractive power after adaptive adjustment of the human eye. The common sight mark on the market is the eye chart box. When testing vision, you can turn out any row of letters for testing by rotating the knob. And use a sight mark projector for testing, which can project various required sight marks at a distance, and realize the switching of sight marks through the control of the motor. In the intelligent detection stage, VR devices are used for vision compensation and detection, and VR technology is used to design the display image, adjust the lens combination position or liquid lens until the subject can see the image clearly to obtain refractive data. The above technologies are devices that assist subjective optometry and realize optometry glasses fitting, which can improve the accuracy of subjective optometry. However, the existing near and far vision detection has the following disadvantages:

1. Traditional eye charts need to be made by yourself for different distances. Usually, there are eye charts with different distances (5m, 3m, 1m, 60cm, 40cm, 33cm). The distance cannot be measured continuously, and the vision of the human eye at a 1′ viewing angle to judge the closest and farthest distances cannot be obtained.

2. The use scenarios of traditional eye charts for near and far vision testing are limited. Testing needs to be performed at standard near and far distances, and it takes up a large space.

3. When using traditional eye charts to test near and far vision, the difference in pupil size between different patients will affect the similarity of the image formed by the human eye on the eye chart. During the test, there will be certain differences in the visual targets, which will reduce the applicability to different populations.

4. Intelligent vision testing based on VR devices can only be used for subjective glasses fitting, and the vision chart cannot test vision at different distances, and cannot perform quantitative testing of vision range.

Summary of the invention

In order to solve the above technical problems, the present invention provides a VR measurement system and method for detecting the visual acuity of human eyes at different distances.

To achieve the above object, the present invention is implemented according to the following technical solutions:

One of the purposes of the present invention is to provide a VR measurement system for detecting the visual acuity of human eyes at different distances, comprising a VR optical system and a Badal optical system;

The VR optical system includes a third lens and a fourth lens along the optical axis from the image plane to the object plane. The object plane side of the fourth lens is provided with an OLED screen that can move in the horizontal direction. The OLED screen is connected to a computer host. The OLED screen is used to display an E-shaped visual acuity chart, and each time a visual mark is switched to display a random E-shaped visual mark;

The Badal optical system includes a first lens, a first right-angle reflecting prism, a second right-angle reflecting prism, and a second lens in sequence from the image plane to the object plane along the optical axis, the first right-angle reflecting prism and the second right-angle reflecting prism are symmetrically arranged, a third right-angle reflecting prism and a fourth right-angle reflecting prism that can be synchronously moved in the vertical direction are arranged directly above the first right-angle reflecting prism and the second right-angle reflecting prism, the third right-angle reflecting prism and the fourth right-angle reflecting prism are symmetrically arranged, the first lens and the second lens are the same, and the first right-angle reflecting prism, the second right-angle reflecting prism, the third right-angle reflecting prism and the fourth right-angle reflecting prism are the same;

The OLED screen serves as a light source to emit a light beam, most of which passes through the third lens and the fourth lens into the Badal optical system, passes through the second lens, and is reflected by the second right-angle reflection prism, the fourth right-angle reflection prism, the third right-angle reflection prism, and the first right-angle reflection prism in sequence before passing through the first lens into the human eye.

Furthermore, the third lens is a double-cemented lens, the object side of the third lens is concave, and the image side is convex, the light beam is focused after passing through the third lens, and the fourth lens is a plano-concave lens, the object side of the fourth lens is flat, and the image side is concave; the center interval between the third lens and the fourth lens is 0.5 mm.

Furthermore, the first lens and the second lens are both doublet lenses, the object side of the first lens is convex and the image side is concave; the object side of the second lens is concave and the image side is convex.

Furthermore, the pupil of the human eye is located at the front focus of the first lens, and the angle α between the visual axis and the optical axis is obtained by the following formula:

Where: _h1 is the aperture of the first lens, _f1 is the focal length of the first lens.

Further, the distance that the third right-angle reflecting prism and the fourth right-angle reflecting prism move synchronously in the vertical direction is L, which is calculated by the following process:

The relationship between the human eye image distance l _e ′ and the human eye refractive power D is:

Among them: D<0 indicates myopia, D>0 indicates hyperopia;

The object distance l for the second lens is:

Gauss formula The image distance l of the second lens (6) is obtained as:

The obtained ΔL is:

Then the moving distances of the third right-angle reflecting prism and the fourth right-angle reflecting prism are:

Wherein L<0 indicates that the third right-angle reflecting prism and the fourth right-angle reflecting prism move downward synchronously, and L>0 indicates that the third right-angle reflecting prism and the fourth right-angle reflecting prism move upward synchronously.

The second object of the present invention is to provide a VR measurement method for detecting the visual acuity of the human eye at different distances, using the above-mentioned VR measurement system for detecting the visual acuity of the human eye at different distances to perform measurements, specifically including basic optometry measurement and visual acuity range measurement;

Among them, basic optometry measurement includes the following steps:

S1, obtain the visual angle value of the E-shaped sight mark and start measuring;

S2, obtaining the viewing angle value of the current E-shaped sight mark, randomly generating an E-shaped sight mark in the E direction according to the viewing angle value, and displaying it in the center of the OLED screen;

S3, the user places the human eye close to the front focus of the first lens and observes the direction of the E-shaped sight mark; if the direction of the current E-shaped sight mark is correctly judged twice, the next viewing angle value is obtained and the step S2 is returned; if the direction of the current E-shaped sight mark is incorrectly judged less than twice, the step S2 is returned; if the direction of the current E-shaped sight mark is incorrectly judged twice, the step S4 is executed;

S4, writing the previous set of viewing angle values into a computer host as the subjective vision of the human eye;

S5, replace the visual angle value of the E-letter sight mark with 1′, move the Badal optical system until the user judges it is clear, and record the position s1;

S6, continue to move the Badal optical system until the user is blurred, and record the position s2 again;

S7, judging whether the number of current position information is 4, if not 4, moving the Badal optical system in the reverse direction to return to the recording position in step S5; if 4, executing step S8;

S8, after the test is finished, the four position information is written into the computer host, the average value of the four positions is used as the calculation parameter of the subjective prescription, and the difference between the front and rear positions is used as the lens accommodation power;

Visual range measurement involves the following steps:

1) Get the E-shaped sight mark with a 1′ visual angle value and start measuring;

2) Slowly move the OLED screen until the user determines the clear position and records the position;

3) The user continues to move the OLED screen back and forth at this position until the user determines the specific position where the E logo becomes blurred, and records the position x1 as the user's farthest visible distance;

4) Continue to move the OLED screen until the user determines the blurry position and records the position;

5) The user continues to move the OLED screen back and forth at this position until the user determines the specific position where the E logo becomes blurred, and records the position x2 as the user's closest visible distance;

6) After the inspection is completed, write position x1 and position x2 into the computer host to obtain the visual range.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention utilizes the characteristics of constant magnification and constant viewing angle resolution of badal optical imaging angle, and combines it with VR vision tester to realize the detection of specific distances of far and near vision, and the detection distance is 5m to 25cm.

2. The measurement method used by the subjective optometry device of the present invention is a continuous zoom method, but unlike the mainstream technology on the market, the present invention uses the Badal optical system to partially adjust the optical path to achieve refractive stimulation and refractive correction, thereby measuring the maximum adjustment range of the lens and the refractive coefficient to achieve autonomous glasses fitting. Its advantages are that it is beneficial to the characteristics of the Badal system itself, keeping the sight mark and the human eye in the same object-image conjugation and the same viewing angle, and improving the applicability of the detection device data to different patients; and it can achieve a large range of refractive correction, which can reach ±20D, and is applicable to a wide range of people; the focusing movement distance is small and the accuracy is high. Compared with existing continuous zoom devices (such as VR detection devices, etc.) and insert-type devices (such as adjustable detection devices, vision boxes, etc.), the VR measurement system for detecting human eye vision at different distances of the present invention can improve the applicability of detection device data to different patients, is simpler to operate, has a short detection time, a large measurement refractive range, and a lower detection cost. Most importantly, the subjective refractive state data is sufficient, and the refractive coefficient, maximum lens adjustment range, near vision and far vision detection can be realized, and the function of autonomous glasses fitting can be realized, and it can also be used as an effect detection device for corrective instruments.

3. The present invention uses an OLED screen as a vision chart and places a VR system in front of the vision chart, which can not only magnify the OLED screen and reduce the size of the device, but also realize the change of the sight mark detection distance, thereby increasing the near vision and far vision detection of the subjective refractive state and achieving fully accurate detection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a VR measurement system for detecting human vision at different distances according to the present invention.

FIG. 2 is a front view of a VR measurement system for detecting human vision at different distances according to the present invention.

Figure 3 is a schematic diagram of the object-side telecentric optical path.

FIG4 shows the working principle of the Badal optical system: (a) optical principle diagram of myopia and emmetropia before adjustment; (b) optical principle diagram of myopia after adjustment.

Figure 5 is a schematic diagram of VR imaging principles.

FIG. 6 is a schematic diagram of drawing a single E sight mark.

FIG. 7 is a schematic diagram of the far and near vision ranges.

FIG8 is a flow chart of basic optometry measurement.

FIG. 9 is a flow chart of visual acuity range measurement.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

Example 1

As shown in FIG. 1 and FIG. 2 , this embodiment exemplarily shows a VR measurement system for detecting the visual acuity of human eyes at different distances, including a VR optical system and a Badal optical system;

The VR optical system includes a third lens 7 and a fourth lens 8 along the optical axis from the image plane to the object plane. The object plane side of the fourth lens 8 is provided with an OLED screen that can move in the horizontal direction. Specifically, in this embodiment, the OLED screen can be installed on an X-axis linear slide for movement. The OLED screen is connected to a computer host. The OLED screen is used to display an E-shaped visual acuity chart, and each time it switches to display a visual mark facing a random E-shaped visual mark; the third lens 7 is a double-cemented lens, the object plane side of the third lens 7 is a concave surface, and the image plane side is a convex surface. The light beam is focused after passing through the third lens 7, and the fourth lens 8 is a plano-concave lens, the object plane side of the fourth lens 8 is a plane, and the image plane side is a concave surface; the center interval between the third lens 7 and the fourth lens 8 is 0.5 mm, and the third lens 7 and the fourth lens 8 can make the visual mark form a virtual image at a standard distance to meet the detection requirements.

The optical schematic diagram of the VR system is shown in FIG5 . The system uses the third lens 7 and the fourth lens 8 to realize small-volume virtual imaging. By placing a tiny sight mark within 1 times the focal length, it is magnified into a virtual image at close range and no longer requires an actual optical screen to receive it. This greatly shortens the length of the overall optical path and the volume of the instrument design, avoids the influence of the limited space and environment of the real scene, and makes it more convenient for the subsequent combination and linkage of the subjective eye test device with other eye detection instruments.

In this embodiment, the design parameters of the E-shaped visual acuity chart are in accordance with international practice, follow the 1-minute visual angle imaging principle, and are designed in accordance with GB11533-89. The visual angle of the visual mark in the visual acuity chart increases at a rate of 100.1, and the logarithm of this rate of increase is taken as the visual acuity corresponding to the visual mark of different visual angles. The visual mark adopts a square E-shaped visual mark with three equal strokes, and each gap of the visual mark is 1/5 of the side length of the square. In this module, the E-shaped visual mark is split into five parts, three equal large rectangular blocks and two equal small rectangular blocks. A small rectangular block is extracted, and its width and height are calculated according to the visual angle and PPD, as shown in Figure 6:

PPD is the number of pixels occupied by each field of view of the VR system, and α is the visual angle of the human eye. This system only displays one E-shaped sight mark for the user to judge each time, eliminating the error in the vision test result caused by the "crowding phenomenon", so that the result of the vision test is only related to the visual angle of the sight mark, and the direction of the sight mark is randomly generated to prevent users from identifying the direction by memory.

The Badal optical system includes a first lens 1, a first right-angle reflection prism 2, a second right-angle reflection prism 5, and a second lens 6 in sequence along the optical axis from the image plane to the object plane. The first right-angle reflection prism 2 and the second right-angle reflection prism 5 are symmetrically arranged. A third right-angle reflection prism 3 and a fourth right-angle reflection prism 4 that can move synchronously in the vertical direction are provided directly above the first right-angle reflection prism 2 and the second right-angle reflection prism 5. Specifically, in this embodiment, the third right-angle reflection prism 3 and the fourth right-angle reflection prism 4 can be installed on an X-axis linear slide. The third right-angle reflection prism 3 and the fourth right-angle reflection prism 4 are symmetrically arranged. The first lens 1 and the second lens 6 are the same. The first right-angle reflecting prism 2, the second right-angle reflecting prism 5, the third right-angle reflecting prism 3 and the fourth right-angle reflecting prism 4 are the same; the first lens 1 and the second lens 6 are both double-cemented lenses, the object side of the first lens 1 is convex, and the image side is concave; the object side of the second lens 6 is concave, and the image side is convex; the first lens 1 and the second lens 6 are combined together in the initial position to form a telescopic system that can transmit information, the first right-angle reflecting prism 2, the second right-angle reflecting prism 5, the third right-angle reflecting prism 3 and the fourth right-angle reflecting prism 4 are on the original telescopic system, and the refractive power is changed by increasing the optical path, thereby compensating for the refractive error of the human eye and correcting the vision.

The macula is the place where the visual cells are most densely packed. The images that the human eye can see are formed here. The line connecting it and the image node of the human eye is the visual axis. In order to prevent the angle between the pupil and the optical axis from changing due to the rotation of the eyeball or the difference in the pupil of the human eye during detection, we use lens 1 and the human eye to form an object-side telecentric system as shown in Figure 3. The human eye pupil is located at the front focus of lens 1, and the angle α between the visual axis and the optical axis can be obtained by the formula:

That is, the angle between the visual axis and the optical axis depends only on the aperture and focal length of lens L1, which means that no matter how the sight mark moves or how the pupil of the human eye differs, the light must pass through the center of the pupil after being focused by lens L1.

Since the first lens 1 and the second lens 6 with the same focal length are used, when the sight mark is placed at infinity, the vertical axis magnification of the system will always be -1 and the angular magnification will not change, thereby ensuring that different people see the same distant sight mark, avoiding the differentiation of sight mark imaging and improving the applicability to users.

In this embodiment, the working principle of the Badal optical system is as follows: the third right-angle reflection prism 3 and the fourth right-angle reflection prism 4 in the system will move up and down to change the distance between the first lens 1 and the second lens 6. If the distance between the first lens 1 and the second lens 6 is greater than the front focal length of the first lens 1, the light beam will be focused when passing through the first lens 1; if the distance between the first lens 1 and the second lens 6 is less than the front focal length of the first lens 1, the light beam will diverge when passing through the first lens 1.

The linear relationship between the vertical moving distance and the diopter of the third right-angle prism 3 and the fourth right-angle prism 4 in the Badal optical system is calculated as follows:

As shown in Figure 4, the blue light indicates that the fundus of a normal human eye with a diopter of 0D is imaged at r, and the red light indicates that the fundus with a diopter of D is imaged at r'. D<0 0 indicates myopia, and D>0 indicates hyperopia.

The relationship between the human eye image distance l _e ′ and the human eye refractive power D in the system is:

The object distance l of the second lens 6 is:

Substitute l into Gauss's formula The image distance l' of the second lens 6 is obtained as follows:

The ΔL can be obtained as:

Then the combined moving distance of the third right-angle reflecting prism 3 and the fourth right-angle reflecting prism 4 is:

Wherein: L<0 indicates that the third right-angle reflecting prism 3 and the fourth right-angle reflecting prism 4 move downward, and L>0 indicates that the third right-angle reflecting prism 3 and the fourth right-angle reflecting prism 4 move upward.

The lens of the human eye is similar to a positive lens, but its optical refractive index changes in a gradient. This structure of the lens can reduce the spherical aberration of the cornea to a certain extent and improve the imaging quality of the eye. An important function of the lens is adjustment, that is, it plays a focusing role when imaging objects at different distances, ensuring that the objects at different distances can be accurately imaged on the retina. The adjustment of the lens is achieved through the extension and contraction of the ciliary muscle to pull the suspensory ligament attached to it and its own elasticity. Therefore, under the refractive stimulation of the Badal system, an elastic range will be formed by the adjustment of the lens and muscles. Most modern subjective and objective optometry devices cannot detect the maximum distance of this lens adjustment. According to the data of the reference paper, the difference in the lens adjustment range between myopic eyes and non-myopic eyes under refractive stimulation is statistically significant, which can be used as a reference data for doctors to diagnose myopia trends and carry out reasonable prevention and treatment.

Through the refractive stimulation and linear relationship characteristics of the Badal system, the refractive adjustment range and refractive power can be achieved. By utilizing the telescope system with the same focal length and the characteristics of the Badal system itself, the sight mark and the human eye are in conjugation with each other and have the same viewing angle, thereby improving the applicability and standardization of the detection device data for different patients.

The OLED screen serves as a light source to emit a light beam, most of which passes through the third lens 7 and the fourth lens 8 to enter the Badal optical system, passes through the second lens 6, and is reflected by the second right-angle reflection prism 5, the fourth right-angle reflection prism 4, the third right-angle reflection prism 3, and the first right-angle reflection prism 2 in sequence before passing through the first lens 1 to enter the human eye.

The present invention can measure the distance of near vision and far vision, and can quantify the visual distance. By utilizing the constant angular magnification of the badal optical system, combined with VR, the human eye can view the virtual image of the E-mark at different distances, so that the detection of far vision and near vision is not limited to the standard distance, but the E-mark with an angular resolution of 1' can be observed at 5m to 33cm, so as to judge the farthest observation distance from the perspective of far vision and the closest observation distance from the perspective of near vision, as shown in Figure 7, which provides a more scientific data measurement method for the focal position of vision. Specifically, the following functions are realized:

1. Realize multi-distance and same-angle resolution detection

The VR system can move the OLED screen back and forth accurately by relying on the X-axis linear slide. Due to the principle of object-image conjugation, the movement of the object can change the detection distance. By utilizing the Badal imaging magnification and imaging angle of view invariance characteristics, the influence of inconsistent imaging angles of different object positions in a single VR system can be avoided, so that the human eye resolution angle is not affected by the imaging distance of the VR during the detection process at different distances. It also avoids the different imaging sizes that may be generated when detecting at different distances under the traditional eye chart, resulting in reduced detection accuracy, and improves the accuracy and applicability of human eye refractive detection.

2. Supplement the test data of visual range

The VR system can move the OLED screen through the X-axis linear slide to achieve vision detection at different distances (5m to 25cm, etc.), detect the farthest distance the subject can see clearly and the closest distance the subject can see clearly when Badal is not adjusted, and detect the closest distance the subject can see clearly and the farthest distance the subject can see clearly after Badal adjustment, that is, when vision is corrected. The vision range that the subject can see clearly can be detected, thereby reducing the difficulty for ordinary people to analyze the correction effect independently, improving the applicability at home, in underdeveloped areas and without the accompaniment of professionals, and also providing a means of detecting the effects of vision correction instruments that are becoming popular on the market, detecting the vision range before correction and the vision range after correction, making the results more convincing.

3. Supplement the data of near and far vision test

The VR system can move the OLED screen through the X-axis linear slide to achieve vision testing at different distances (such as 5m to 25cm). It can detect the visual acuity of the subject at the standard far vision distance and the standard near vision distance without Badal adjustment, and detect the visual acuity of the subject at the standard far vision distance and the standard near vision distance after Badal adjustment, i.e., vision correction. It can make up for the fact that most optometry institutions now only use far vision as the standard for optometry evaluation, greatly improving the accuracy of optometry glasses. Not only that, it can also be used as an evaluation indicator for amblyopia in young children, presbyopia in the elderly, and double vision function in adolescents, to achieve early prevention and regulation and treatment.

4. Improve the randomness of sight marks and detection accuracy

The OLED screen can switch the sight mark at will without delay, avoiding the influence of the patient's memory on subjective judgment. It can change the sight mark image according to different testing needs and accurately detect the patient's subjective refractive state.

Example 2

As shown in FIG8 , this embodiment exemplarily uses the VR measurement system for detecting the visual acuity of the human eye at different distances to perform basic optometry measurement, and the specific steps are as follows:

S1, obtain the visual angle value of the E-shaped sight mark and start measuring;

S2, obtaining the viewing angle value of the current E-shaped sight mark, randomly generating an E-shaped sight mark in the E direction according to the viewing angle value, and displaying it in the center of the OLED screen;

S3, the user places the human eye close to the front focus of the first lens and observes the direction of the E-shaped sight mark; if the direction of the current E-shaped sight mark is correctly judged twice, the next viewing angle value is obtained and the step S2 is returned; if the direction of the current E-shaped sight mark is incorrectly judged less than twice, the step S2 is returned; if the direction of the current E-shaped sight mark is incorrectly judged twice, the step S4 is executed;

S4, writing the previous set of viewing angle values into a computer host as the subjective vision of the human eye;

S5, replace the visual angle value of the E-letter sight mark with 1′, move the Badal optical system until the user judges it is clear, and record the position s1;

S6, continue to move the Badal optical system until the user is blurred, and record the position s2 again;

S7, judging whether the number of current position information is 4, if not 4, moving the Badal optical system in the reverse direction to return to the recording position in step S5; if 4, executing step S8;

S8, after the test is finished, the four position information is written into the computer host, the average value of the four positions is used as the calculation parameter of the subjective prescription, and the difference between the front and rear positions is used as the lens accommodation power;

Example 3

As shown in FIG9 , this embodiment exemplarily uses the above-mentioned VR measurement system for detecting the visual acuity of the human eye at different distances to measure the visual acuity range, and the specific steps are as follows:

7) Get the E-shaped sight mark with a 1′ visual angle value and start measuring;

8) Slowly move the OLED screen until the user determines the clear position and records the position;

9) The user continues to move the OLED screen back and forth at this position until the user determines the specific position where the E logo becomes blurred, and records the position x1 as the user's farthest visible distance;

10) Continue to move the OLED screen until the user determines the blurry position and records the position;

11) The user continues to move the OLED screen back and forth at this position until the user determines the specific position where the E logo becomes blurred, and records the position x2 as the user's closest visible distance;

12) After the inspection is completed, write position x1 and position x2 into the computer host to obtain the visual range.

The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims (6)

1. A VR measurement system for detecting human vision at different distances, characterized in that it includes a VR optical system and a Badal optical system; The VR optical system comprises a third lens (7) and a fourth lens (8) along the optical axis from the image plane to the object plane, an OLED screen movable in the horizontal direction is provided on the object plane side of the fourth lens (8), the OLED screen is connected to a computer host, and the OLED screen is used to display an E-shaped visual acuity chart, and each time the visual acuity chart is switched to display an E-shaped visual acuity chart facing a random direction; The Badal optical system comprises, from the image plane to the object plane along the optical axis, a first lens (1), a first right-angle reflecting prism (2), a second right-angle reflecting prism (5), and a second lens (6), wherein the first right-angle reflecting prism (2) and the second right-angle reflecting prism (5) are symmetrically arranged, and a third right-angle reflecting prism (3) and a fourth right-angle reflecting prism (4) which can be synchronously moved in the vertical direction are arranged directly above the first right-angle reflecting prism (2) and the second right-angle reflecting prism (5), and the third right-angle reflecting prism (3) and the fourth right-angle reflecting prism (4) are symmetrically arranged, the first lens (1) and the second lens (6) are the same, and the first right-angle reflecting prism (2), the second right-angle reflecting prism (5), the third right-angle reflecting prism (3), and the fourth right-angle reflecting prism (4) are the same; The OLED screen serves as a light source to emit a light beam, and most of the light beam passes through the third lens (7) and the fourth lens (8) to enter the Badal optical system, passes through the second lens (6), and is reflected by the second right-angle reflection prism (5), the fourth right-angle reflection prism (4), the third right-angle reflection prism (3), and the first right-angle reflection prism (2) in sequence before passing through the first lens (1) to enter the human eye. 2. The VR measurement system for detecting human eye vision at different distances according to claim 1 is characterized in that: the third lens (7) is a doublet lens, the object side of the third lens (7) is a concave surface, and the image side is a convex surface, and the light beam is focused after passing through the third lens (7); the fourth lens (8) is a plano-concave lens, the object side of the fourth lens (8) is a flat surface, and the image side is a concave surface; the center interval between the third lens (7) and the fourth lens (8) is 0.5 mm. 3. The VR measurement system for detecting human eye vision at different distances according to claim 1 is characterized in that: the first lens (1) and the second lens (6) are both double-cemented lenses, the object side of the first lens (1) is convex and the image side is concave; the object side of the second lens (6) is concave and the image side is convex. 4. The VR measurement system for detecting human eye vision at different distances according to claim 1, characterized in that: the pupil of the human eye is located at the front focus of the first lens (1), and the angle α between the visual axis and the optical axis is obtained by the following formula: Wherein: _h1 is the aperture of the first lens (1), and _f1 is the focal length of the first lens (1). 5. The VR measurement system for detecting human eye vision at different distances according to claim 1, characterized in that: the distance that the third right-angle reflection prism (3) and the fourth right-angle reflection prism (4) move synchronously in the vertical direction is L, which is calculated by the following process: The relationship between the human eye image distance l _e ′ and the human eye refractive power D is: Among them: D<0 indicates myopia, D>0 indicates hyperopia; The object distance l for the second lens (6) is: Gauss formula The image distance l of the second lens (6) is obtained as: The obtained ΔL is: Then the moving distances of the third right-angle reflecting prism (3) and the fourth right-angle reflecting prism (4) are: Wherein L<0 indicates that the third right-angle reflection prism (3) and the fourth right-angle reflection prism (4) move downward synchronously, and L>0 indicates that the third right-angle reflection prism (3) and the fourth right-angle reflection prism (4) move upward synchronously. 6. A VR measurement method for detecting human eye vision at different distances, characterized in that the measurement is performed using the VR measurement system for detecting human eye vision at different distances as described in any one of claims 1 to 5, specifically including basic optometry measurement and vision range measurement; Among them, basic optometry measurement includes the following steps: S1, obtain the visual angle value of the E-shaped sight mark and start measuring; S2, obtaining the viewing angle value of the current E-shaped sight mark, randomly generating an E-shaped sight mark in the E direction according to the viewing angle value, and displaying it in the center of the OLED screen; S3, the user places the human eye close to the front focus of the first lens and observes the direction of the E-shaped sight mark; if the direction of the current E-shaped sight mark is correctly judged twice, the next viewing angle value is obtained and the step S2 is returned; if the direction of the current E-shaped sight mark is incorrectly judged less than twice, the step S2 is returned; if the direction of the current E-shaped sight mark is incorrectly judged twice, the step S4 is executed; S4, writing the previous set of viewing angle values into a computer host as the subjective vision of the human eye; S5, replace the visual angle value of the E-letter sight mark with 1′, move the Badal optical system until the user judges it is clear, and record the position s1; S6, continue to move the Badal optical system until the user is blurred, and record the position s2 again; S7, judging whether the number of current position information is 4, if not 4, moving the Badal optical system in the reverse direction to return to the recording position in step S5; if 4, executing step S8; S8, after the test is finished, the four position information is written into the computer host, the average value of the four positions is used as the calculation parameter of the subjective prescription, and the difference between the front and rear positions is used as the lens accommodation power; The visual range measurement includes the following steps: 1) Get the E-shaped sight mark with a 1′ visual angle value and start measuring; 2) Slowly move the OLED screen until the user determines the clear position and records the position; 3) The user continues to move the OLED screen back and forth at this position until the user determines the specific position where the E logo becomes blurred, and records the position x1 as the user's farthest visible distance; 4) Continue to move the OLED screen until the user determines the blurry position and records the position; 5) The user continues to move the OLED screen back and forth at this position until the user determines the specific position where the E logo becomes blurred, and records the position x2 as the user's closest visible distance; 6) After the inspection is completed, write position x1 and position x2 into the computer host to obtain the visual range.