(1) the eye distance is too close. The adjustment ability of young eyes is very strong. When the distance between books and eyes is up to 7-10 centimeters, it can still see objects, but if we read frequently at this distance, writing will make the eye's regulation abnormal, so that we can form inflectional (regulatory) myopia and so called pseudmyopia. If the long-term excessive regulation, not flexible because of ciliary muscle, caused by excessive regulation to strengthen the convergence effect, make the extraocular muscle to exert pressure on the eyeball, increased intraocular pressure, intraocular tissue hyperemia, and teenagers eyeball tissue delicate, eyeball compression gradually extended, eyeball becomes longer, than the normal value on the formation of the shaft myopia, the so-called true myopia. The normal reading distance should be 30-35 centimeters.
(2) long eye time. Read and write homework, watching TV for 3-4 hours without a break, even the night before sleep and rest, which not only affect the body health, but also make the eyes burden, intraocular muscles long time in a state of tension and not rest, in the course of time, when looking at the distance, the eye muscles can relax in spasticity. So far are fuzzy and the formation of myopia. Generally speaking, reading and writing or watching TV for 40-50 minutes should rest for a moment or look far away.
(3) the light is too strong or too weak. If the light is too strong, such as sunlight written, will cause a strong reflection, irritation of the eyes, make eye discomfort, it is difficult to see the font, on the contrary, the light is too weak, writing poor lighting, eyes can not clearly see the font, the head will move, close to the book, the above two kinds of circumstances can eye fatigue, eye regulation of excessive or spasm of myopia.
(4) reading in the driving or walking. It is bad for the eyes to read or read in a walking car while walking. Because the car is shaking, the body is shaking, the distance between the eyes and books is not fixed, and the lighting condition is not good, which aggravates the burden of the eyes. Often, it can cause myopia.
(5) lie in a book. It is a bad habit to read in bed. Because people's eyes to maintain the level of the state of reading, so that adjustment and collection (influx) agreed to reduce eye fatigue. If you read on the bed, eyes in the state level, distance between eyes and a book is not consistent with the view about the books are inconsistent, uneven illumination, will make the eyes and easy to adjust tension in the book closer to the eyes, it can aggravate the burden on the eyes 2-3 times, day long form myopia.
(6) lack of sleep. When the lack of sleep, the second day tired, dizzy, the brain is not fully rest, failed to eliminate fatigue, heavier burden on the eyes, the occurrence of myopia. Lack of sleep is one of the most important reasons for the formation of myopia.