Eye asymmetry, which usually refers to the position of two eyes that do not look straight ahead at the same time, is also called strabismus and is a very common condition in ophthalmology. Depending on the manifestation, it can be divided into internal strabismus, external strabismus and vertical strabismus, as well as some special types of strabismus. This condition is caused by abnormalities in the function of the extraocular muscles, so the eye cannot be maintained in its normal position, and it requires early examination and treatment. Some of them can be corrected by conservative treatment, such as wearing glasses, which can be used for the correction of moderate internal strabismus; for exotropia or vertical strabismus, surgery is usually required, and the timing of surgery should be mastered before the development of stereoscopic vision in both eyes is impaired.