Definition of Vision Aids: Any device or equipment that improves the mobility of a person with low vision is called a vision aid. Vision aids are similar to hearing aids, just as hearing aids enable a person with poor hearing to hear sounds he could not hear, and vision aids enable a person with low vision to see clearly what he could not see or could not see. Additional explanation of the definition: 1. Vision aids are only an aid to help patients, that’s all, they do not have any therapeutic effect, nor do they improve the vision itself, and certainly do not cause the vision itself to get worse. 2.No vision aid can replace all the functions of the normal eye. 3.Patients with low vision often need more than one kind of visual aids because they have different needs for work, life and study. 4.The more optical lenses of the visual aids, the worse the image quality; the magnification of the visual aids is inversely proportional to the visible range. 5.In the health care of low vision and its rehabilitation, the visual aid is only a part, but not the whole.