WHO said that ensuring enough outdoor activity time is the best way to prevent myopia.From small to large, according to the line of scientific and technological development, experts say that the reasons for high myopia rate are: reading posture, sufficient light, TV, computer, mobile phone, tablet.At present, experts at home and abroad agree that the lack of time for outdoor activities, that is, exposure to sunlight, is the main reason for myopia.Mobile phones and tablets have very limited effect on myopia.