CN110063708B

CN110063708B - Calibration visual chart and visual chart using method

Info

Publication number: CN110063708B
Application number: CN201910422517.2A
Authority: CN
Inventors: 朱爱斌; 吕银月; 陈威
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-05-21
Filing date: 2019-05-21
Publication date: 2022-04-19
Anticipated expiration: 2039-05-21
Also published as: CN110063708A

Abstract

The invention discloses a calibration visual chart, which comprises a plurality of lines of E-shaped visual targets arranged from top to bottom from big to small, wherein the E-shaped visual targets in each line have the same size and are equal in interval, each E-shaped visual target comprises 3 black stripes I arranged in parallel, black stripes II which are connected to the end parts of the 3 black stripes I and are vertical to the black stripes I, and white stripes arranged between the adjacent black stripes I, and the E-shaped visual targets in the plurality of lines contain E-shaped visual targets with different black and white stripe contrasts and different width and width contrasts of the black stripes I and the white stripes; the invention objectively and scientifically reflects the perception rule of the eyes on the contrast sensitivity change by setting the 'black-white contrast' and 'spatial frequency' in each line of sighting marks and designing the calibration visual chart according to the technical parameters; the device is suitable for health physical examination of normal vision people, and is also suitable for detection diagnosis, ocular optical lens fitting and correction rehabilitation of various weak vision people.

Description

Calibration visual chart and visual chart using method

Technical Field

The invention pertains to a device for testing eyes; the technical field of eye examination instruments, in particular to a calibration visual chart and a visual chart using method.

Background

For the detection of children's eyesight in modern medical treatment, a standard eyesight comparison table (the eyesight level of a subject is judged by distinguishing the orientations of E with different sizes) is generally adopted, and an adult asks questions of children to obtain a corresponding detection result; if the standard visual acuity comparison chart is zoomed into the liquid crystal touch screen according to a certain distance proportion (the space distance between the testee and the calibration visual acuity chart: the distance between the eyes of the testee and the liquid crystal touch screen), and the standard visual acuity comparison chart is used as a detection image for detecting the children, the adults are still required to give guidance to the children to ask questions, and the children can speak corresponding results.

However, the whole process of searching for "E" is rather tedious, since the E-character optotype has a black-and-white contrast of 100%, and the scale size of the stripes is 1: 1, the problem of crowded vision of partial children is easily caused, namely, the symbol E with the leftmost and the rightmost has stronger resolving power, and the symbol with the middle has weaker resolving power; therefore, in the tedious testing process, children often give their guessed results randomly under repeated asking by adults, and thus the obtained vision testing data only has reference value and cannot truly represent the vision level of children.

In recent years, it has been found that the visual deterioration of the amblyopia children is more remarkable at low contrast, and the therapeutic effect of the amblyopia is to judge not only the visual acuity with high contrast of 100%, but also the visual acuity with low contrast such as 75%, 50% and 25%.

In addition, for various reasons, some children wear the whole standard visual contrast chart, and only the children can recognize the position of the E, so that the orientation of the E can be accurately spoken according to the previous memory, and the detection result can be directly distorted.

Disclosure of Invention

In view of the above, the present invention provides a calibration eye chart and an eye chart using method, in which the "black-white contrast" and "spatial frequency" of each line of visual targets are set, and the calibration eye chart designed according to the technical parameters objectively and scientifically reflects the perception law of eyes on contrast sensitivity change; the device is suitable for health physical examination of normal vision people, and is also suitable for detection diagnosis, ocular optical lens fitting and correction rehabilitation of various weak vision people.

In order to achieve the purpose, the calibration eye chart comprises a plurality of rows of E-shaped visual targets which are arranged from top to bottom from large to small, wherein the E-shaped visual targets in each row are identical in size and equal in spacing, each E-shaped visual target comprises 3 black stripes I which are arranged in parallel, black stripes II which are connected to the end parts of the 3 black stripes I and are vertical to the black stripes I and white stripes which are arranged between the adjacent black stripes I, and the E-shaped visual targets in the plurality of rows comprise E-shaped visual targets which are different in black-white contrast of the black stripes I and the white stripes and different in width-width contrast of the black stripes I and the white stripes.

Further, the black-white contrast ratio of the black stripe I and the white stripe is set to be 10-100%.

Further, the black-and-white contrast of the black stripe I and the white stripe is set to 10%, 20%, 50%, 75%, and 100%.

Further, the width contrast ratio of the black stripe I and the white stripe is set to be 20-500%.

Further, the black stripe I and white stripe width-to-width contrast ratio is set to 20%, 40%, 50%, 100%, 200%, 300%, and 500%.

Furthermore, the black-white contrast and the width contrast of the adjacent E-shaped sighting marks are different.

The invention also discloses a using method for calibrating the visual chart, which comprises the following steps:

1) the testee carries out standard test, tests through a standard logarithmic visual chart and records the vision test value Bs of two eyes of the testee;

2) the testee carries out calibration test, tests the logarithmic visual acuity chart by quickly passing through the calibration three times and records the vision test value Ds, the black-white contrast test value dh and the stripe width contrast test value dk of two eyes of the testee;

3) when Ds is larger than or equal to Bs, the detected person performs standard lens fitting by taking the Bs as a vision value;

4) when Ds is smaller than Bs and Dh is larger than Bs, selecting a 75% black-white contrast visual chart, a 50% black-white contrast visual chart, a 25% black-white contrast visual chart or a 10% black-white contrast to test and recording a black-white contrast test value Dh, and selecting the black-white contrast of the E-shaped visual standard as the standard when the Dh value fails to pass the detected black-white contrast;

5) when Ds is smaller than Bs and dh is smaller than Bs, selecting a 20% wide-narrow contrast visual chart, a 40% wide-narrow contrast visual chart, a 50% wide-narrow contrast visual chart, a 100% wide-narrow contrast visual chart, a 200% wide-narrow contrast visual chart, a 300% wide-narrow contrast visual chart or a 500% wide-narrow contrast visual chart for testing and recording a black-white contrast test value Dk, and selecting the E-shaped visual chart with the standard that the Dk value does not pass the test as the wide-narrow contrast of the visual chart.

Further, the color of the lens is adjusted during fitting through the black-white contrast test value Dh, and the size and the range of the lens are adjusted during fitting through the width contrast test value Dk.

Further, the vision rehabilitation exercise is carried out on the myopia patients by selecting the stripes with the ratio of the black-white contrast test value Dh and the width contrast test value Dk.

Further, the use method of the calibration eye chart is applied to a mobile phone, and the brightness of the mobile phone and the distance between a screen and eyes are controlled by selecting the black-white contrast test value Dh and the width contrast test value Dk.

The invention has the beneficial effects that:

1. the calibration visual chart has the advantages of simple structure, easy recording and statistical analysis, strong fairness, high accuracy and universal applicability, can be used for detecting far vision and near vision, can also be used for detecting astigmatism and identifying far vision and near vision, is suitable for health physical examination of normal vision people, and is also suitable for detection diagnosis, ocular optical fitting and correction rehabilitation of various weak vision people.

2. The calibration eye chart provided by the invention objectively and scientifically reflects the perception rule of eyes on contrast sensitivity change by setting the black-white contrast and the spatial frequency of each line of sighting marks according to the calibration eye chart designed by the technical parameters; the device is suitable for health physical examination of normal vision people, and is also suitable for detection diagnosis, ocular optical lens fitting and correction rehabilitation of various weak vision people.

Drawings

FIG. 1 is a front view of a conventional E-word table;

FIG. 2 is a front view of a calibration eye chart according to the present invention;

FIG. 3 is a front view of a calibration chart of the present invention for 50% blackness;

FIG. 4 is a comparison graph of raster frequency adjustment in a calibration eye chart according to the present invention;

FIG. 5 is a comparison graph of raster frequency adjustment in a calibration eye chart according to the present invention;

FIG. 6 is a comparison graph of luminance contrast adjustment in a calibration eye chart according to the present invention.

Description of the drawings: 1-E-shaped sighting target with 100% black-white contrast and 100% width contrast; 2-E-shaped sighting marks with 100% black-white contrast and 50% width contrast; 3-E-shaped sighting marks with 50% black-white contrast and 100% width contrast; 4-E-shaped sighting marks with 100% black-white contrast and 200% width contrast; 5-75% of black-white contrast and 50% of width contrast.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 2 and fig. 3, the calibration eye chart according to the present invention includes a plurality of rows of "E" shaped targets arranged from top to bottom, the "E" shaped targets in each row have the same size and the same distance, the E "shaped targets include 3 black stripes I arranged in parallel, black stripes II connected to the ends of the 3 black stripes I and vertical to the black stripes I, and white stripes arranged between adjacent black stripes I, and the plurality of rows of" E "shaped targets include" E "shaped targets having different black-white contrasts of the black stripes I and the white stripes, and different width contrasts of the black stripes I and the white stripes.

In a preferred embodiment, the black-white contrast of the black stripe I and the white stripe is set to 10 to 100%.

In a preferred embodiment, the black-and-white contrast ratio of the black stripe I and the white stripe is set to 10%, 20%, 50%, 75%, and 100%.

In a preferred embodiment, the width-to-width contrast ratio of the black stripe I and the white stripe is set to 20% to 500%.

In a preferred embodiment, the black stripe I and the white stripe are set to have a width-to-width contrast ratio of 20%, 40%, 50%, 100%, 200%, 300%, and 500%.

In a preferred embodiment, adjacent E-shaped sighting marks have different black-white contrasts and different width contrasts.

Fig. 4 and 5 are contrast charts of the adjustment of the width and the width of the white stripe in the calibration eye chart according to the present invention, and the spatial frequency is one of the parameters of the grating; the unit is the period per degree (cpd), the number of grating periods can be seen in a 1-degree view angle, one period corresponds to the minimum pattern of the formed grating and consists of a black bar and a white bar, and the higher the spatial frequency of the grating is, the more vertical bars are in each unit view angle; when the spatial frequency of the raster is increased to a limit, the raster is no longer visible, the highest spatial frequency that the human eye can perceive is 30cpd, and the corresponding vision is (20/20).

FIG. 6 is a contrast chart illustrating the adjustment of brightness contrast in the calibration chart according to the present invention, wherein the contrast of the brightness contrast is defined as the ratio of the maximum brightness value and the average brightness value of the contrast:

Contrast＝(Lmax-Lmin)/(Lmax+Lmin)

the maximum contrast and the maximum value of the sine wave represent the relationship between brightness change and position, and the average brightness does not change along with the increase of the contrast; contrast varies between 0 and 1 (0% and 100%), luminance contrast is not visible (below 0.3%) when it is small, and spatial frequencies above 30cpd are not visible whether the contrast is high or low.

The contrast sensitivity measurement in this embodiment can also be described in decibels (dB), using a logarithmic scale to correspond to the physiological function of the visual system:

Contrast(dB)＝10×log

the following table represents the correspondence of partial points

Contrast (%)	Contrast ratio (dB)
		100％	0dB
10％	10dB
		1％	20dB
0.11％	30dB

Another important parameter of contrast sensitivity is temporal frequency, and neurophysiological studies have shown that the visual system is composed of many subsystems with different sensitivities to spatial and temporal information; one distinction at present is the M-cell system and the P-cell system; m-cell systems are more sensitive to low spatial and high temporal frequencies, while P-cell systems are more sensitive to high spatial and low temporal frequencies; both glaucoma and amblyopia can contribute to contrast sensitivity.

The influence of the time frequency on the contrast or the dynamic contrast can be realized by a periodically-reversed sinusoidal grating; white vertical bars and black vertical bars appear alternately; the temporal frequency is expressed in Cycles Per Second (CPS), or Hz flicker is a special case of dynamic contrast sensitivity, the spatial frequency being so low that only one bar can be seen in a given time.

Also discloses a using method for calibrating the visual chart, which comprises the following steps:

In a preferred embodiment, the color of the lens is adjusted during fitting through the black-white contrast test value Dh, and the size and the range of the lens are adjusted during fitting through the wide-narrow contrast test value Dk.

In a preferred embodiment, the eyesight rehabilitation exercise is carried out on the myopic person by selecting the stripes with the ratio of the black-white contrast test value Dh and the width contrast test value Dk.

In a preferred embodiment, the method for using the calibration eye chart is applied to a mobile phone, the brightness of the mobile phone and the distance between a screen and eyes are controlled by selecting the black-and-white contrast test value Dh and the wide-and-narrow contrast test value Dk, the mobile phone is used more and more seriously due to unscientific use of the mobile phone and the screen, the mobile phone is used correctly by selecting the black-and-white contrast test value Dh, the wide-and-narrow contrast test value Dk and the corrected vision test value Ds, and the application method is used in cooperation with a mobile terminal of hami data communication technology limited, and the operation process is as follows:

1) detecting the working state of a display screen of the mobile phone, and starting a front camera by a background when the display screen is activated;

2) capturing scene information in a visible range of a mobile phone screen by a front-facing camera, and identifying whether face information exists in the scene information;

3) when the scene information contains the face information, the background opens the infrared device and sends infrared rays to the eyes of the user, and the eyes are inspected through the retina shadow-testing mirror;

4) and adjusting the font size of the mobile phone screen according to the eyesight and the face of the user.

Before detecting the working state of the display screen of the mobile phone, the method further comprises the following steps: if the user selects the function mode, for example, if the user selects the manual setting mode, the mobile phone adjusts the font size of the mobile phone screen according to the black-and-white contrast test value Dh, the width contrast test value Dk and the corrected vision test value Ds of the user, which specifically includes: inputting vision parameters of the eyes of the individual; the mobile phone adjusts the font size and brightness of the mobile phone screen according to the vision parameters of the user.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. The utility model provides a calibration eye chart, includes from big to little from the top down multirow "E" word sighting target of arranging, and "E" word sighting target size is the same and the interval is equal in every line, "E" word sighting target includes 3 parallel arrangement's black stripe I, connect 3 black stripe I tip and with black stripe I vertical black stripe II and set up the white stripe between adjacent black stripe I, its characterized in that: the multi-line E-shaped visual target comprises an E-shaped visual target with different black stripe I and white stripe black-white contrasts and different black stripe I and white stripe width contrasts.

2. A calibrated eye chart according to claim 1, wherein: the black-white contrast ratio of the black stripe I and the white stripe is set to be 10-100%.

3. A calibrated eye chart according to claim 2, wherein: the black-and-white contrast of the black stripe I and the white stripe was set to 10%, 20%, 50%, 75%, and 100%.

4. A calibrated eye chart according to claim 1, wherein: the width contrast ratio of the black stripe I and the white stripe is set to be 20-500%.

5. A calibrated eye chart according to claim 1, wherein: the width-to-width contrast ratio of the black stripe I and the white stripe is set to 20%, 40%, 50%, 100%, 200%, 300%, and 500%.

6. A calibrated eye chart according to any of claims 1 to 5, wherein: the black-white contrast and the width contrast of the adjacent E-shaped visual targets are different.