The prescription of glasses should be adapted to the specific situation of the individual’s eyes as the best, with a low or high are not conducive to eye health, not only can not play a corrective role, a long time, but also may lead to increased visual impairment. Whether nearsighted or farsighted, the purpose of wearing glasses is to correct vision and help adjust the focal length. If the glasses are low, the ciliary muscle may become over-adjusted and spasmodic, causing fatigue and possibly aggravating vision loss. High prescription eyeglasses may cause dizziness, sometimes only a little higher than the appropriate prescription, which does not cause blurred vision, but also impairs vision and may accelerate the process of myopia or farsightedness. In addition, under the premise that it suits your eyes and ensures comfortable and clear vision, you can make slight adjustments according to the environment in which you wear it. If you work for a long time, you can make your glasses lower when you wear your eyes, while people who need to wear glasses outside for a long time can adjust them higher under the guidance of a doctor. However, all of the above operations should be within the permissible range, and the optometrist should give reasonable advice, and try to avoid too high or too low. Most opticians have the function of optometry when dispensing glasses, but it is not only through optometry that the prescription of glasses can be determined, but also a full set of eye examinations should be carried out to determine the prescription of glasses more accurately. Especially for the first time, people should visit a professional eye hospital to find out whether their eyes are nearsighted, farsighted, astigmatism, high eye pressure, fundus lesions and other specific conditions, and according to these conditions, choose the right glasses for themselves.