If there is myopia in one eye and hyperopia in the other eye, it is called refractive error, and this condition has a greater impact on the eye. The first, and most common symptom, is a loss of vision. Second, because the difference between the two eyes is too large, it is easy to have eye fatigue symptoms, such as eye pain, photophobia, tearing, or accompanied by headaches, especially forehead headaches, dizziness, for this condition must be corrected early. Third, in the case of children, it is easy to lead to the occurrence of amblyopia and strabismus. In order for the eyes to see clearly, many people will take a compensatory head position or squint to see things.