Conventional optometry results only let the refractive error see clearly, while the purpose of medical optometry is not only to let the patient see clearly, after the optometry prescription can see clearly, but also feel comfortable wearing glasses and can read lasting. The content of medical optometry includes the degree of optometry, eye position, adjustment power, binocular monocular function, vergence collection function, binocular adjustment balance, and identification of the dominant eye, and finally, the scientific prescription is issued by integrating the above situation. The goal is to achieve clear, comfortable and long-lasting reading with lenses. The effect of medical optometry is significantly better than conventional optometry, as those who wear frames or contact lenses after medical optometry are less prone to visual fatigue, and the photometric status of myopia is more stable, slowing or even stopping its development. Conventional optometry, on the other hand, is prone to visual fatigue and even myopia deepening (de-focusing effect) because other aspects of visual function are not taken into account, i.e., binocular monocular function, stereopsis, etc. Objective optometry, objective optometry is also divided into shadowing optometry and computerized optometry, according to the results of objective optometry and then subjective optometry, subjective optometry is the core part of medical optometry. Usually, we also refer to the process of subjective optometry as medical six-step optometry. The first step is called the best visual acuity at the time of the first most positive spherical lens (on the basis of the results of the examination shadow or computerized optometry). The second step is the initial red-green test. These two steps are for precise spherical lens prescription, which is what we usually call myopia. The third step is the crossed column lens to adjust the axis and degree of astigmatism. Currently, the crossed column lens is the most classic and reliable tool for precise astigmatism and axis position. The fourth step is to perform the best visual acuity test again at the most positive spherical lens based on the accurate astigmatism. The fifth step again performs the red-green test. This again pinpoints the degree of myopia again. The sixth step is a binocular balance test. The purpose of the test is to make binocular vision more comfortable and more in line with the physiological requirements of our eyes. Finally, according to the individual differences of each person can also make some adjustments, and finally get a myopic friends to see things clearly and comfortably optometry results. This process is called medical optometry.