Specific prescription principles are as follows: 1. Medical optometry must first be conducted to determine the presence of refractive error, if any, to clarify the nature of refractive error, is myopia, or farsightedness, whether there is astigmatism, and then, to accurately determine the amount of refractive error, astigmatism, also need to determine the direction of the astigmatic axis. In the case of children and adolescents, optometry can be performed by dilated pupils. If pseudomyopia is confirmed, it should be treated as pseudomyopia and glasses are not necessary. 2, about -1.00 degrees of low myopia vision is about 0.5 to 0.6, if there is no difficulty in learning or working, sitting in front of the classroom to read the words on the blackboard is not difficult, not to wear glasses is not impossible. Or, you can wear glasses only when you need them. However, if the refractive error of myopia is greater than -1.00 degrees, the difficulty of seeing far away, affecting the classroom learning, it is better to wear glasses. The degree of glasses worn should be the lowest degree of corrected visual acuity of 1.0. Excessive correction can lead to a farsighted state, and the increase in the burden of regulation can cause visual fatigue. 3, high myopia in order to maximize visual acuity, the full amount of correction. However, the first time with glasses, too high degree is often difficult to adapt at once, still will appear some uncomfortable symptoms, including dizziness can not walk, which should be appropriate to reduce the degree of glasses, to wear no discomfort shall prevail, – general reduction amount of about -1.00 degrees to -3.00 degrees. After adaptation, the next prescription can gradually increase the degree, until the results of the optometry – consistent. 4, if the myopic refraction of both eyes is different or one eye has myopia, – eye is orthopia or even farsighted, the difference between the refraction of both eyes is more than 300 degrees, wearing glasses with a huge difference in refraction of both eyes can cause the retina of both eyes, the size of the object is not equal, each other can not be combined as -, like picking something – head light The eye of the big refractive power can be reduced to the extent that both eyes can tolerate the lenses, in order to adapt to the correction of the lenses. Myopia after the glasses problem: 1, glasses is good to wear all the time? Or sometimes wear sometimes take off good? If in a 200 degrees of myopia or more often wear for good. Take off the glasses, because the regulation and radiation disorders cause vision fatigue, it is better to wear often not to take off. 2, after wearing glasses will not wear more and more deep? People will stop developing around the age of 18-20, and most myopia refractive errors are generally lower than -6.00 degrees. In other words, during the youth development period, the mild and slow development of myopia refraction deepens is the law of simple myopia itself, and not the result of wearing glasses, of course, not the more glasses worn the deeper myopia. 3, wear the glasses is not impossible to take off? It is not impossible to take them off, wearing glasses can correct vision, take them off and can not see is the need to wear glasses. Optically in accordance with the results of medical optometry to formulate glasses suitable for correcting myopia, in order to obtain the best corrected vision, so myopic patients in the optometry prescription should pay attention to medical correction.