1.Too close eye contact:
The normal reading distance should be 30-875px. Myopia caused by long-term use of eyes is more common. Teenagers have a strong eye accommodation, and can still see objects when the distance between books and eyes is 7-250px. However, if you often read or write at this distance, the adjustment of the eyes will be extremely tense, thus forming accommodative myopia,
So called pseudomyopia. If the long-term over regulation, the ciliary muscles can not flex flexibly, and the excessive adjustment will lead to the enhancement of the radiation effect, which will make the extraocular muscles exert pressure on the eyeball, increase the intraocular pressure, and congest the intraocular tissues. In addition, young people’s eyeball tissue is delicate, the eyeball wall is compressed gradually, and the anterior and posterior axes of the eyeball become longer, which exceeds the normal value and forms axial myopia, so-called true myopia.
- The use of eyes is too long.
Read books and watch TV for 3-4 hours without rest, even late at night. It makes the eyes overburdened, and the muscles inside and outside the eyes are in a tense state for a long time without rest. Over time, when looking at a distance, the muscles of the eyes can not be relaxed and show spasmodic state. Thus, when you look at the distance, you will feel blurred and form myopia.
It is generally advocated that reading, writing or watching TV for 40-50 minutes should take a rest or look at the distance for a while.
- The lighting is too strong or too weak.
If the light is too strong, it will cause strong reflection, stimulate the eyes, make the eyes feel uncomfortable, it is difficult to see the font; on the contrary, the light is too weak, the written lighting is not enough, the eyes can not clearly see the font, the head will move forward, close to the book, the above two situations can cause eye fatigue, excessive adjustment of the eyes or spasm and form myopia.
- Nutritional and physical factors:
In addition to unsanitary use of eyes, lack of sleep, eye fatigue and other factors, myopia has a certain relationship with nutritional constitution. Excessive nutrition intake and weak physique will also cause myopia.