Automatic flip mirror – the principle of action 1, myopia prevention and control principle: “adjustment lag” (i.e. adjustment is not sensitive) is the key link in the occurrence and development of myopia in students. This mirror can constantly flip the front lens so that the focus of attention from the front fog (virtual) type jump to 5 meters away from the far side, and then jump back to the front of the eye, thus significantly improve the eye regulation sensitivity, to prevent the occurrence of myopia, development. 2, improve vision principle: (1) adjustment sensitivity training can improve visual sensitivity and thus improve visual acuity; (2) the current lens flip up when a transient visual haze, flip down immediately become clear, this hazy clear flip process, is the process of vision growth, the United States famous myopia expert Professor Bates also found that the flip mirror can significantly improve the visual acuity of amblyopic eyes and most myopic eyes. 3, to prevent the symptoms of eye fatigue: eye fatigue is the root of the disease is regulation fatigue, so training the adjustment sensitivity can be prevented. 4.Preventing presbyopia: The cause of presbyopia is the aging of the crystal and the decrease of adjustment power. Therefore, training the adjustment sensitivity can prevent it.