Lack of eye hygiene and long periods of excessive close work are the most important environmental factors that cause myopia. Many sources have shown that the incidence of myopia is much higher among primary and secondary school students who do not pay attention to eye hygiene than those who do. There are many cases of not paying attention to eye hygiene, such as improper reading and writing posture, reading in bed, reading in a turbulent carriage, reading while walking, reading in direct sunlight, reading in dim light. Some people in reading and writing, like to twist the body crooked head, eyes and the distance of the book is very close; some people pick up a novel book, read with great interest, continuous long time to read, refuse to let go, so that the eye muscle is often in a state of tension; some people do not pay attention to the light intensity when reading and writing, sometimes in the strong sunlight reading, so that the eye is stimulated for a longer time, some in the dim light Reading books, because the light is too dark and the handwriting is not clear, it is natural to put the eyes very close; some people look at comic books fascinated, even when walking or sitting in the car, so that the distance between the eyes and books will change with the body position changes; others like to lie in bed to read, the posture is skewed, the book can not be put right, the book and the distance between the two eyes is not the same, one eye far from the book must make efforts to the other side Oblique look, and often books on the light is not enough, you must use your eyes to look hard to do. The above-mentioned lack of attention to eye hygiene is bound to increase the burden of eye regulation and contribute to myopia.