A myopic patient with a difference of 400 diopters between the two eyes is called a refractive error, which cannot be corrected by wearing normal frames, but can be corrected by wearing contact lenses or having surgery. If the difference between the two eyes of a myopic patient is not the same, and the difference is more than 300 degrees, it is called refractive error, and if the difference between the two eyes is 400 degrees, it belongs to refractive error. At this time, the patient can not be corrected by wearing frame glasses, because the magnification of different glasses lenses is not the same, the difference between the two eyes is too large, which will lead to see the size of the object is not the same and thus the formation of double vision. At this point, patients can consider wearing contact lenses or undergoing refractive surgery, both of which can improve the patient’s corrected visual acuity and do not cause double vision and other symptoms. The decision as to which method of correction is appropriate should be made by your doctor after an in-person examination.