To know how many degrees of myopia you have, you need an optometry test to determine. Myopia is a common ophthalmologic disease, belonging to a type of refractive error, generally due to the role of heredity and unhealthy eye habits, patients with myopia growth, vision will gradually decline, must be through the medical treatment, to do optometry examination to get the accurate myopia degree. Especially for children, in order to eliminate the ciliary muscle contraction caused by the adjustment effect on the results of the optometry, but also need to perform dilated optometry, in order to get the accurate myopia. Myopia is not fixed, and may gradually aggravate, patients need to pay attention to maintain good eye habits, try to control the growth of myopia, such as reducing the time of close-distance use of the eyes, avoiding the subway, buses and other shaky and dim environment to use the eyes. It is recommended that myopic patients should consult a doctor in time to assess their condition and follow the doctor’s instructions for treatment.