The fact that the pupil is dilated and says that the patient is not nearsighted means that the patient has pseudomyopia, not true myopia. Pseudomyopia occurs mostly because of prolonged eye fatigue caused by ciliary muscle spasm, the eye localized pupil dilation, the ciliary muscle can be fully relaxed, the corresponding pseudomyopia will be relieved, or even disappear. Therefore, it is common that some patients have myopia before pupil dilation, but after pupil dilation, the degree of myopia disappears. If the myopia is true myopia, even if the eye is partially dilated after the optometry, the myopia can still be detected, because true myopia is often caused by the growth of the eye axis, and will not be relieved by dilating the pupil.