However, in the widely used vertical chart, there are only two large charts at the top, three charts in a row, eight charts in a row, and two charts in the bottom row. One visual acuity index represents an improvement of 0.05, while eight consecutive visual acuity indexes are 0.0 125.
Extended data:
Precautions:
1, frequent blinking: Many people blink less frequently than usual when using the computer. Reducing the number of blinks will reduce the lubrication effect of tears on the eyeball, leading to frequent dryness and discomfort. If you must use the computer for a long time, you can consider artificial tears.
2, using eye protection, green is good for children's eye health, because the colors of various objects in nature absorb and reflect light to different degrees.
3, eye movement to alleviate eye fatigue: first look at the target object 5 meters away for half a minute to relax the eye muscles and flatten the lens. Look at the target at 30 cm for half a minute, which makes the eye muscles tense and the lens thicken. Look at the distance alternately, every time 10- 15 minutes, 3-4 times a day.
Avoid direct sunlight from a distance, and it is best to see more green trees and grass. It is suitable for developing primary and secondary school students, and has the functions of recovering eye fatigue and protecting eyesight. It has a certain therapeutic effect on pseudomyopia and can prevent myopia.
Baidu encyclopedia-vision
Baidu encyclopedia-eye chart