When a patient with strabismus closes one eye, the other deviated eye automatically returns to the correct position, which is a normal phenomenon. Strabismus refers to the direction of the eyes' gaze not being parallel; when one eye is looking straight ahead at a target, the gaze of the other eye will deviate. Based on the direction of deviation, strabismus can be classified into several types such as esotropia (inward deviation), exotropia (outward deviation), and vertical strabismus. When one eye is covered, the originally deviated eye will move to the correct position to clearly see the target directly in front; however, the covered eye will then exhibit deviation. Therefore, strabismus is not eliminated but merely appears from an external perspective that the deviated eye has returned to its normal position. To completely eliminate the symptoms of strabismus, surgery is required for correction.