CN1072478C - Eye adjusting curve measuring apparatus - Google Patents

Abstract

An eye accommodation curve measurement device, comprising an optical system 1 composed of mutually perpendicular stimulus light paths and response light paths, a closed-loop control motor component 2 that drives the movement of the stimulus optics in the stimulus light path, and a closed-loop drive that moves the response optics in the response light path The control motor component 3 and the computer 4 that respectively read in the voltage signal of stimulating the visual target position and the voltage signal of the responding visual target position and input the input level of the closed-loop control motor component. The invention can realize the adjustment curve measurement of the whole visual range of the test eye, and has high measurement accuracy and high reliability.

Description

Eye Accommodation Curve Measuring Device

The invention relates to a device for measuring the focusing ability of human eye lens.

The lens (Lens) is a "lens" composed of transparent thin fibers in the eyeball. When people look at objects at different distances, they will be processed by the central nervous system according to the Brul of the image film produced on the retina. Signals are sent through the ciliary muscle to control the shape and curvature of the lens, so that the target to be watched forms a clear image on the retina—that is, minimizes the blur (Minimize the Brul). Obviously, changing the distance of the visual target will automatically adjust the lens of the human eye, and different focusing curves will appear according to its focusing ability. Can be used for scientific research. Therefore, people have designed a variety of devices related to measuring the focusing ability of the human eye. For example, the US Patent Office announced on February 26, 1980 an invention patent for controlling the "method and device for the visual refractive state of the eye". (Patent No. 4190332, application date 771014), the device of this invention patent is composed of a control part for controlling the refractive state of the subject's eye and an objective diopter (or fundus reflection diopter) measuring part in a closed-loop connection structure, which can automatically measure the subject's diopter. The far-point focusing ability of the eye. Due to the closed-loop connection of the two main components of the device, the optotype located in the refractive state control part can move within the full visual range, but since the optotype for measuring the refractive state is controlled by the closed-loop feedback of the diopter signal , although it can automatically measure the hyperopic point of the subject, it can only measure a unique hyperopic point for each subject, that is, it cannot measure the focusing curve of its full visual range, which leads to the invention patent Due to the limitation of application, for example, it is difficult to measure the reliable far-point degree of focus for cataract patients; and because of the well-known fact that the eye is a black body, this makes the objective diopter measurement part accept the test from the fundus of the test eye. The reflected signal is less than one ten-thousandth of the reflected light. This signal is very weak, and the light source brightness of the refractive state control part must be enhanced. However, if the light is too strong, even if infrared rays are used, it is not good for the test eye. This is a contradiction; In addition, the movement system of the visual target in the refraction state control part is directly linked with the drive motor, and the position of the infrared light bar and the position of the measurement lens in the diopter measurement part are linked with the motor, which makes it difficult to implement the accuracy requirements, such as In addition, convenient calibration is required, and the accuracy cannot be guaranteed; moreover, reflectors are respectively arranged in the incident and reflection optical paths in the refracting part of the objective lens, which also cause troubles in implementation because of the consistency of the length of the optical paths.

The purpose of the present invention is to provide a device that can measure the focusing curve of the test eye by taking points in the whole visual range.

Technical solution of the present invention is as follows:

1. According to the principle of classic Badal lens, the large-scale collimation nonlinear motion of an object at infinity to a very close distance is converted into a small range of linear movement of the visual target on the optical axis of the convex lens from the focal length to the mirror surface , so that the eye's focusing ability D (in diopters) is expressed as: $\mathrm{D.}=\frac{1}{L}$ Expressed, L is the physical location of the object, in meters;

2. Set two optical paths, horizontal and vertical. The visual mark patterns in the two optical paths are different (that is, the spatial frequency components contained are different), and the two optical paths share a prism and a measuring lens (Badallens). If the target is used as the imaging target for stimulating the test eye, the target in the other optical path is the imaging response target. Firstly, the distance of the stimulus target is given to image the stimulus of the test eye, and then the distance of the response target is adjusted to make the imaging reach The minimum ambiguity, while the test eye sees both the stimulus and the response targets clearly, and the adjustment range of the response targets is used to determine the eye's focusing ability. Based on this, two optical paths perpendicular to each other are designed. Their structures are the same. One is the stimulating optical path and the other is the responding optical path. They are independent of each other, that is, they are open-loop coupling;

3. The movement of the visual target in the optical path is driven by a motor, but the moving distance of the visual target is not represented by the number of revolutions of the motor, but is converted and read by the voltage value of the linear resistance contact point where the visual target is located;

4. The servo loop of the driving motor adopts a closed-loop negative feedback structure to ensure that the influence and instability of the dead zone range of the motor rotation are eliminated, so that the visual target can move sensitively along the optical axis and the position is stable; it works together with the linear resistance position feedback The accuracy of the measurement position is also guaranteed.

5. The visual target should be movable within the full range of vision, and the diopter of the corresponding position can be measured at any point, and the data collection and processing are controlled by the computer, and the accommodation curve of the test eye is displayed.

As can be seen from the above, the present invention includes a horizontal light path (stimulation light path) and a vertical light path (response light path) with a shared prism and measuring lens, and the visual marks of the two light paths are imaged on the retina of the test eye after sharing the prism and measuring lens; The horizontal optical path includes sequentially optically connected stimulating point light sources, stimulating parallel beam forming lenses, stimulating visual targets, and shared prisms and measuring lenses; the vertical optical path includes sequentially optically connecting responding point light sources, responding parallel beam forming lenses, and responding visual targets , and a shared prism and measuring lens. The distance between the two-way (stimulus and response) parallel beam forming lens and the shared triangular lens covers the entire visual range, and the two-way (stimulus and response) optotypes are driven by corresponding closed-loop control motors to move along the optical axis The driving input voltage of the stimulating closed-loop control motor matched with the stimulating visual mark in the horizontal light path is controlled by a computer, and the voltage signal of the visual mark position is sent to the computer for processing; the response closed-loop control motor drive matched with the responsive visual mark in the vertical light path The input voltage is adjusted manually, and the voltage signal of the visual mark position is sent to the computer for processing.

The advantages of the present invention are as follows:

1. It can test the focusing ability of the subject's eye lens in the whole visual range, and display the focusing curve, which provides useful information in clinical and scientific research. For example, according to the existing technology, a corresponding one The tested eye can only test one far point of vision, which often leads to unreliable test results for those with cataracts. However, using the device of the present invention, the system can be determined from the deviation of the curve due to the detection of points taken from the whole visual range. It is caused by cataract disease; 2. Due to the open-loop connection of the stimulus light path and the response light path, there is no reduction in the sensitivity of the detection signal due to the black body absorption of the test eye; or in order to compensate for the small reflection coefficient of the fundus, it is necessary to receive a strong test eye 3. Since the closed-loop control motor is used to drive the visual target, there is no dead zone in the motor rotation, so that the visual target moves smoothly along the optical axis, and the position scale of the visual target is not fixed. It depends on the number of revolutions of the motor, but is expressed by the voltage value of the target position; it overcomes the measurement error caused by the error between the transmission belt and the motor rotation; 4. The position of the target, that is, the reading of the distance, is detected by a computer to eliminate Subjective errors caused by the use of scale readings are eliminated; 5. The imaging of the response visual target is adjusted by the subject's hand, which conforms to the principle of "Minimize the Brue" of the visual target imaging on the retina, that is, the test high reliability.

Accompanying drawing of the present invention is as follows:

Fig. 1 is a schematic diagram of the overall structure of the present invention.

Fig. 2 is a schematic diagram of the closed-loop control motor component of the stimulating optotype of the present invention.

Fig. 3 is a structural schematic diagram of the closed-loop control motor component in response to the visual target of the present invention.

Fig. 4 and Fig. 5 are respectively the embodiment diagrams of Fig. 2 and Fig. 3 of the present invention.

Fig. 6 is a schematic diagram of the mechanical structure of the motor-driven visual target of the present invention.

Fig. 7 is a schematic structural view of the coordinate frame of the present invention.

Fig. 8 is a schematic diagram of a stimulus optotype of the present invention.

Fig. 9 is a schematic diagram of the responsive optotype of the present invention.

Fig. 9-1 is a schematic diagram of the overall structure of another embodiment of the present invention.

Figures 10 to 17 are test results using the device of the present invention.

A preferred embodiment of the present invention is given below with reference to FIGS. 1 to 9 , and further technical details of the present invention are provided in conjunction with the description of the embodiment.

Please refer to Fig. 1, as shown in the figure, the present invention comprises the optical system 1 that is formed by mutually perpendicular stimulation light path 11 and response light path 12, drives the stimulus visual mark 113 in the stimulation light path 11 to move along the optical axis and stimulates the closed-loop control motor Component 2, a response closed-loop control motor component 3 that drives the response optotype 123 in the response optical path 12 to move along the optical axis, and a computer connected to the two-way (stimulus optical path and response optical path) closed-loop control motor components 2 and 3 respectively 4. Also as shown in the figure, the stimulating optical path 11 includes a stimulating point light source 111, a stimulating parallel light beam forming lens 112, a stimulating visual target 113, and a shared triangular prism 13 and a measuring lens 14 that are sequentially optically connected; the stimulating visual target 113 is stimulated by a closed-loop control motor. The drive of the component 2 moves along the optical axis, and its image appears on the retina of the subject's eye after passing through the shared triangular prism 13 and the measuring lens 14; the response optical path 12 of the same optical path structure includes a response point light source 121, a response The parallel light beam forms a lens 122 , a responsive visual mark 123 , and a common triangular prism 13 and measuring lens 14 . In this way, by stimulating the visual target 113 to form an image on the test eye, and then adjusting the position of the response visual target 123, the imaging on the visual target can achieve the minimum blur. Because the spatial frequency components contained in the graphics of the stimulus optotype 113 and the response optotype 123 are different, the subject can easily judge the clear imaging of the response optotype 123, and due to the well-known fact, the imaging of objects on the retina is in the form of oscillations. And reach minimum ambiguity, therefore, the moving position of stimulus visual mark 113 is taken point to go to start stimulating closed-loop control motor member 2 action by the D/A output of computer 4, after visual eye sees the image of stimulus visual mark 113 clearly, again Manual adjustment makes the motor component 3 move back and forth in response to the closed-loop control, so that the response visual mark 123 reaches the minimum ambiguity in the imaging of the visual eye.

Please refer to Fig. 2, as can be seen from the figure, the stimulation closed-loop control motor component 2 includes a stimulation drive amplifier 21, a stimulation motor 22 driven by the stimulation drive amplifier 21, and an optotype position stimulation output part 23 connected with the stimulation motor 22 electromechanically. , and the stimulus output unit 23 is connected with the stimulus drive amplifier 21 in a closed loop negative feedback. Like this, because of the closed-loop negative feedback of the stimulating motor 22, when the D/A part of the computer 4 starts the stimulating motor 22 to rotate according to the set value, the stimulating motor 22 can rotate smoothly, thereby ensuring that the stimulating visual mark 113 is straight along the The optical axis moves, and after the position of the stimulus visual target 113 is electromechanically converted, its coordinate value is sent to the computer 4 by the visual target position output unit 23, and the computer 4 performs data processing.

Referring to Fig. 3, it can be seen from the figure that the responsive closed-loop control motor component 3 includes a responsive driving amplifier 31 connected in a circuit, a responsive motor 32, and an optotype position responsive output part 33 connected electromechanically with the responsive motor 32. , and the response output part 33 is connected to the response drive amplifier 31 with negative feedback output to form a closed-loop negative feedback control for the response motor 32. The response drive amplifier 31 receives the adjustment signal from the manual starting unit 310 to make the response motor 32 rotate.

Please refer to FIG. 4 , FIG. 6 , FIG. 7 and FIG. 8 at the same time, they are embodiments of the stimulating closed-loop control motor component 2 that drives the stimulating visual target 113 to move along the optical axis. Wherein the stimulation drive amplifier 21 includes a stimulation pre-amplification unit 211, a stimulation negative feedback access unit 212 and a stimulation power amplifier unit 214 sequentially connected in a circuit. In order to protect the stimulation motor 22, a stimulation limiting protection is also connected before the stimulation power amplifier unit 214. Unit 213 ; the visual target position stimulation output unit 23 includes a stimulation displacement power supply 231 , a stimulation electromechanical conversion unit 232 , a stimulation feedback connection unit 233 and a stimulation output unit 234 sequentially connected in a circuit. The stimulating machine-electric conversion unit 232 is a linear potentiometer, which is in a flat structure, and its length is greater than or equal to the length of the full visual range, and is installed below the stimulating parallel light beam forming lens 112 and the common prism 13, and it is connected with the stimulating The visual target 113 is in point contact, but there is a dead zone when the motor drives the stimulus visual target 113 to move, therefore, the voltage drop per unit length of the linear potentiometer and the voltage of the dead zone must be considered to determine the amplification of the pre-stimulation amplification unit 21 multiple. In this embodiment, the stimulating motor 22 adopts an M28-23 type DC motor, which has a relatively large rotational torque and can overcome relatively large frictional resistance. It should also be pointed out that the high-frequency phase shift correction network composed of resistor R2120 and capacitor C2121 is connected to the stimulation negative feedback access unit 212 for the purpose of eliminating oscillation; and capacitor C2141. It can also be seen from FIG. 6 and FIG. 7 that the stimulating optotype 113 is mounted on the optotype base frame 1130 , and then a compression reed is provided under the base frame 1130 to form a sliding point contact connection with the potentiometer 232 .

Then please refer to Fig. 5, Fig. 6, Fig. 7 and Fig. 9 at the same time, because the structure of Fig. 6 and Fig. 7 can also be used on the driving mechanism to the response visual mark 123, the difference between Fig. 5 and Fig. 4 only lies in the response driving amplifier 311 The input is from the manual adjustment unit 310 rather than being controlled by the computer 4 . Other components: response preamplifier unit 311, response negative feedback access unit 312, response power amplifier unit 314, response limiter protection unit 313, response motor 32 driven by response power amplifier unit 314, and position of response visual mark 123 Response displacement power supply 331 of response output unit 33, response electromechanical conversion unit 332, response feedback connection unit 333 and response output unit 334 structure and mutual connection relationship are all the same as above-mentioned stimulation closed-loop control motor component 2, also point out The difference between the stimulus optotype 113 and the response optotype 123 is only in the pattern. The stimulus optotype 113 has a relatively large image and contains rich spatial frequency components, while the response optotype 123 only presents a small circle. Stimulation optical path 11 and response optical path 12 in the overall structure of the present invention can also be shown in Figure 9-1, change shared measurement lens 14 into lens 114 and lens 124, and are respectively positioned at the front face of shared prism 13, at this moment stimulate The visual target 113 moves between the parallel beam forming lens 112 and the measuring lens 114 ; and the corresponding visual target 123 moves between the parallel beam forming lens and the measuring lens 124 . At last, in order to further illustrate the positive effect of the present invention, we respectively explain as follows to Fig. 10 and Fig. 11, Fig. 12 and Fig. 13, Fig. 14 and Fig. 15, and Fig. 16 and Fig. 17:

Fig. 10 is the curve that uses the device of the present invention to the visual acuity test of a normal-sighted youth, and the scale of X and Y coordinate is represented by D respectively, and X is the location of stimulus visual mark 113 ${\mathrm{D.}}_Y=\frac{1}{L_Y}$ , Y is the position of the response target, ${\mathrm{D.}}_x=\frac{1}{L_x}$ . Among them, the straight line 1 represents the focusing curve of the ideal normal eye, and "+" represents the test result of points taken within the visual range ∞-0.1 meters, corresponding to each D _X position has 8 "+", and the D _X coordinate points are determined by the computer 4 Scaling, while D _Y is manually adjusted by the subject so that the response optotype 123 is determined by minimizing the blurriness of the image on the retina. The 8 "+" lines represent the four round-trip measurement results of D _X from ∞-0.1m, and the square root error is shown in Figure 11.

Figure 12 is the test result for a young man suffering from myopia, as shown in the figure, he has 300 degrees of myopia, and the measurement error is shown in Figure 13.

Fig. 14 is a vision test for an old man, D _Y is taken from 0-9D to test, and its response visual mark 123 is almost at the coordinate height of D _X = 6D, which means that it has 600 myopia and is aging, as shown in Fig. 15 is the corresponding response error.

Figure 16 is also the vision test result of a female elderly subject. The stimulus visual mark 113 is selected from 0 to 9D, and the imaging D value of the corresponding response visual mark 123 is tested. The subject said that he has 400 degrees of myopia , at this time, a certain optical shop measured his vision, but he always felt uncomfortable. It can be seen from the graphic data that the dispersion is very large. Figure 17 shows the corresponding error distribution. According to the doctor's examination, he suffered from cataracts. The reliability of such a measurement curve is difficult to match in the prior art.

Claims (9)

1. A device for measuring an eye accommodation curve, comprising an optical system (1) and a computer (4) composed of mutually perpendicular stimulation optical paths (11) and response optical paths (12); Point light source (111), stimulating parallel light beam forming lens (112), stimulating visual target (113); the response optical path (12) includes sequentially optically connected response point light source (121), responding parallel light beam forming lens (122), Response visual mark (123); And the shared prism (13) and measuring lens (14) that are placed behind this response visual mark (123) and stimulus visual mark (113), it is characterized in that there is also driving stimulus visual mark (113) The stimulating closed-loop control motor member (2) and the driving response optotype (123) that move between the stimulating parallel light forming lens (112) and the shared prism (13) along the optical axis form the lens (122) and the responding parallel light along the optical axis. The response closed-loop control motor component (3) that moves between the shared prisms (13); the driving input voltage of the stimulating closed-loop control motor component (2) is controlled by the computer (4), and the position voltage signal of the stimulating visual target (113) is sent to The computer (4) processes; the driving input voltage of the responsive closed-loop control motor component (3) is manually adjusted, and the positional voltage signal of the responsive visual target (123) is sent to the computer (4) for processing. 2. According to the described eye adjustment curve measuring device of claim 1, it is characterized in that the said stimulating closed-loop control motor component (2) comprises a stimulating drive amplifier (21) and a stimulating motor (22) driven by it, and the stimulating motor (22) ) stimulates the output unit (23) with an electromechanical connection of the visual target position, and the stimulation output unit (23) is connected with the stimulation drive amplifier (21) by a closed-loop negative feedback. 3. According to the described eye accommodation curve measuring device of claim 1, it is characterized in that the said responsive closed-loop control motor component (3) comprises a responsive drive amplifier (31), a responsive motor (32) and a responsive motor connected in sequence in sequence. (32) An optotype position-responsive output part (33) with an electromechanical connection, and the responsive output part (33) is connected with the responsive driving amplifier (31) by a closed-loop negative feedback. 4. According to the described eye adjustment curve measuring device of claim 2, it is characterized in that the stimulation drive amplifier (21) comprises a stimulation pre-amplification unit (211), a stimulation negative feedback access unit (212) and a stimulation negative feedback access unit (212) sequentially connected with a circuit. Stimulation amplifier unit (214). 5. According to the described eye accommodation curve measuring device according to claim 2, it is characterized in that the stimulus output part (23) of the target position comprises a stimulus displacement power supply (231) connected with a circuit in sequence, a stimulus electromechanical conversion unit (232) and stimulus feedback connection unit (233). 6. According to the described eye adjustment curve measuring device of claim 5, it is characterized in that the described stimulating electromechanical conversion unit (232) is a linear potentiometer with a straight structure, and its length is greater than or equal to the full visual range measurement length, It is installed under the stimulating parallel light beam forming lens (112) and the common triangular prism (13), and is in point contact with the mounting seat of the stimulating visual target (113). 7. According to the described eye accommodation curve measuring device of claim 3, it is characterized in that the described response drive amplifier (31) comprises a response front stage amplifying unit (311), a response negative feedback access unit (312) and a response negative feedback access unit (312) sequentially connected with a circuit. Responsive power amplifier unit (314). 8. According to the said eye accommodation curve measurement device of claim 3, it is characterized in that said optotype position response output part (33) comprises a response displacement power supply (331) connected with a circuit in sequence, a response electromechanical conversion unit (332) and a response feedback connection unit (333). 9. According to the described eye adjustment curve measuring device of claim 8, it is characterized in that the described response electromechanical conversion unit (332) is a linear potentiometer with a straight structure, and its length is greater than or equal to the full visual range measurement length, It is installed under the responding parallel light beam forming lens (122) and the shared triangular prism (13), and is in point contact with the installation base of the responding visual mark (123).

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