[Source: Shanghai Market Regulation]
Seeing that the holiday balance is insufficient,
Throughout the holiday,
Are you traveling far to brush the autumn sky?
Or is it an immersive home-based lying flat brush drama?
Your glasses
It may not be for you anymore
With a pair
Clear, comfortable and long-lasting
of glasses need its "blessing"!
Comprehensive refractometer
Comprehensive refractometer, also known as refractive head, lung head or bull's eye, is different from its name, we can think of it as an automated refractive lens box, which integrates ball lenses, cylindrical lenses, prisms and various auxiliary lenses and adjustment components for refraction examination, and realizes the examination of human eye refractive state and visual function through the superimposed combination of lenses on different internal mirror discs.
Perhaps many people's experience of optometry is still limited to the use of computer refractometers and refractive lens boxes.
What's the difference?
Let's analyze it briefly
Similarities and differences between the three instruments!
Similarities
They are the most commonly used refractive instruments and are widely used in medical institutions or glasses manufacturing sites.
Differences
Computerized refractometers are objective refraction devices that directly obtain the diopters of the eye. The accuracy of a computerized refractometer is affected by many factors, so it cannot replace the optometrist's refraction and lens correction techniques, and only provides a useful reference for manual refraction.
Integrated refractometers and refractive lens cases are subjective refractive instruments used to precisely determine the condition of the binocular lenses. However, compared with the traditional refractive lens box, the comprehensive refractometer is more scientific, rigorous and accurate, mainly reflected in the following points:
1
The integrated refractometer replaces lenses with high speed and accuracy, and the examiner does not have to use an audition frame for refraction, reducing eye pressure.
2
When the comprehensive refractometer astigmatizes optometry, the coaxial design of crossed cylindrical mirror and astigmatism can be used to increase the axial position of astigmatism to 1°, and the diopter is accurate to 0.25D (25°). However, the axial direction of astigmatism in traditional lens box refraction relies on computer data, and the axial position and diopter cannot be accurately determined.
3
Comprehensive refractometry myopia refraction can use red-green contrast to determine optimal vision with an accuracy of 0.12D.
4
The comprehensive refractometer can perform visual function examination such as binocular fusion, stereoscopic vision, strabismus, heterophoria, and adjustment force. However, the traditional lens box does not have the relevant aspects of optograms and lens groups, and cannot achieve a comprehensive inspection of the visual function.
The original comprehensive refractometer
There are so many advantages
Then it's the process of refraction
How is that?
Seven-step optometry
1
First of all, you need to use an optometry to initially measure a set of refraction data.
2
Adjust the interpupillary distance according to the value of the refractive sheet, set the value of the refraction sheet to the initial degree, cover the left eye, and measure the right eye first.
3
Increase +75 to +100 degrees to the original degree to artificially create a myopic environment that allows the optometrist to enter the foggy state to relax the eyeballs and maintain this state for 5 to 10 minutes.
4
The optometrist's "maximum diopter for optimal vision" (MPMVA) is obtained by reducing the patient's vision by 25 degrees at a time until the optometrist says it can no longer be improved.
5
For the red and green test, because the wavelength of red light is longer than green light, after entering the eyeball, the two rays will focus in different positions, so when people can just see green light, the red light will be blurred, and vice versa, therefore, it is necessary to carefully schedule the number on the basis of the previous step until the red and green optograms can be seen at the same time.
Red and green optograms
6
The comprehensive refractometer has high speed and accuracy in changing lenses, and the examination determines the astigmatism reading and axial position. Switch the cylindrical lens to the viewport, the patient observes the honeycomb optogram, astigmatism optogram, etc., adjust the cross cylinder, and determine the astigmatism. At the end of the right eye refraction, those who refract the left eye in the same procedure do not have to use the audition frame for refraction, which reduces the pressure on the eye.
Honeycomb optograms
Scattered disc optograms
7
Finally, it is necessary to adjust the visual balance of both eyes and try on the audition frame.
Comprehensive refractometer as
Internationally recognized major,
Standard optometric equipment
How to ensure the accuracy of its refraction results?
On November 4, 2019, the State Administration for Market Regulation issued Document No. 48 "Catalogue of Measuring Instruments Implementing Compulsory Management", which included comprehensive refractometers in the catalogue of measuring instruments subject to compulsory management.
Statutory metrology institutions establish comprehensive refractometer measurement standards in accordance with the verification regulations of JJG1097-2014 "Comprehensive Refractor (Including Eye Chart)", and use the equipped comprehensive refractometer top focus measuring device to verify the measurement parameters such as spherical lensity, cylindrical mirror, axial position, optical center error and other measurement parameters of the comprehensive refractometer to ensure that the measurement value of the comprehensive refractometer in use by medical institutions at all levels and glasses fitting centers is accurate and reliable.
Integrated refractometer top focal measuring device
Vision is the main function of monocular, the most important function of the eye is on the basis of normal vision, to ensure that the eyes are used in concert, clear and comfortable to see the near and far world, although now optometric technology and equipment are very advanced, but refractive error, wearing glasses after many occasions still have certain restrictions, therefore, protecting the eyes is still our first priority!
Technical support of this article:
Shanghai Institute of Metrology and Testing Technology
Hou Rui
* Some images are from the Internet
Contribution: Municipal Institute of Planning
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