The comparison table between the old and new eye charts is as follows:
From May, 2065438 to May, 2002, when I went to a hospital or a medical examination center to check my eyesight, I found that the original eye chart seemed to have changed. Not only can you see clearly when the light box is on, but there is also an extra E in the first line of the eye chart, which is to change from a single target to two targets (two E's).
This is a new version of the national standard of logarithmic visual acuity chart, which has been officially implemented since May 1 2065438. In the future, the hospital eye chart will be gradually replaced by this new version. It is a compulsory standard for general physical examination of children, adolescents and adults aged 3 years and above, as well as near and far vision measurement and visual impairment screening for physical examinations such as enrollment and recruitment.
Extended data:
Professor Mei, the main drafter of the new version of the visual acuity chart and the president of the Ophthalmology and Optometry Hospital of Wenzhou Medical College, said that the new standard has basically not changed in size on the basis of retaining the original visual angle, visual target shape, standard distance, visual target increase rate and visual target record. The obvious change is that the first line (5 points is 4.0) is increased from the original single target to two targets.
This not only improves the measurement of low vision, but also reduces the probability that the first line of sight is guessed. At the same time, the brightness standard of the light box is improved, that is, it is not less than 200 Candeira/square meter, which can prevent testers from not seeing the eye chart clearly because of light and affecting the test results.
The standard eye chart is divided into near eye chart and far eye chart according to the measuring distance and measuring function. The measuring distance of myopia eye chart is 25 cm, which measures myopia vision. The distance measured by the hyperopia instrument is 5 meters, and the distance measured is hyperopia. The most familiar and commonly used is the farsightedness instrument. However, the revised near-far visual acuity chart increases the number of visual targets, improves the uniformity of visual target arrangement, and enhances the accuracy and convenience of vision test.
Baidu encyclopedia-new national vision chart