Strabismus is a condition in which both eyes cannot look at a target at the same time, one eye looks at the target and the other eye deviates from the target, the position of the two eyes is asymmetric, that is, people often say “strabismus”. The eye of the strabismus patient is the orthophoric eye, that is, the external object is imaged on the macula of the eye, and the eye deviating from the target is the strabismus eye, the same external object is imaged on the position other than the macula of the eye. In this way, the same external object cannot be imaged on the corresponding retina of both eyes, which prevents the formation of stereopsis. Therefore, strabismus not only affects the appearance, but more importantly, it affects the establishment of stereopsis or destroys the existing binocular monocular function. Strabismus is divided into two categories: common strabismus and paralytic strabismus. The common causes of common strabismus are: congenital factors; abnormalities in the higher neural reflexes of the brain and the regulation and fusion of the eyes; and a certain relationship with heredity, but most strabismus patients do not have a clear family history. It is closely related to refractive error and is often associated with hyperopia, myopia or astigmatism. Common causes of paralytic strabismus: congenital anomalies, lesions of the nucleus innervating the extraocular muscles and the extraocular muscles themselves; certain diseases may cause such as intracranial tumors, cerebrovascular accidents, inflammation, trauma, diabetes mellitus, and inflammation of the orbit. Some patients with intracranial tumors have symptoms only in the eyes, but other symptoms are later, so they should consult the doctor as early as possible to avoid delaying the treatment of intracranial tumors. First of all, strabismus affects the appearance, which is often the main motivation for patients to seek medical attention; more importantly, strabismus affects the normal development of visual function of both eyes, and in serious cases, there is no stereoscopic vision. Stereoscopic vision is an advanced visual function that only humans and higher animals have, and is one of the prerequisites for people to engage in fine work. Without good stereoscopic vision, looking at any object will be a flat surface without depth and distance; some patients with strabismus will also produce diplopia, i.e., seeing one object as two, and patients can only eliminate diplopia and confusion by visual suppression and establishing abnormal retinal correspondence; most patients with strabismus suffer from amblyopia at the same time. As patients with strabismus use one eye to gaze for a long time, the other eye will cause disuse vision loss or stop development, and later, even if they wear suitable glasses, their vision will not reach normal; when they suffer from strabismus in childhood, they are often discriminated by children and classmates, thus causing great trauma to their mind, resulting in low self-esteem and loneliness, which directly affects the child’s character and psychological development. Strabismus in childhood also affects the development of the entire skeleton, such as congenital paralysis strabismus, which causes contracture of the neck muscles and pathological curvature of the spine, and asymmetric facial development. In addition to the aesthetic effects, strabismus can also have adverse functional consequences. If treated promptly during the visual development period (before the age of 12), in addition to correcting the ocular strabismus, the strabismus can disappear, the spinal curvature and facial development can be adjusted, and the obstacles to the development of stereo vision can be removed. If the treatment is carried out after the development of vision is mature, it can only correct the skew of the eye, and the vision of the strabismic eye will not be improved, nor can it obtain the function of binocular monocularity, which has certain influence on the choice of work and occupation. The timing of surgery for congenital strabismus should be as early as possible, and surgery for infantile strabismus before the age of 2 is best for establishing binocular vision. For patients with late onset of strabismus (after 2 years of age), surgery is generally recommended before school age, which is beneficial to the healthy growth of the child in terms of visual function and psychology. For those with amblyopia, amblyopia should be treated first and surgery should be performed only after the visual acuity of both eyes is balanced. The purpose of strabismus treatment, functional cure: correcting strabismus into orthophoria, creating conditions for establishing normal retinal correspondence, further obtaining monocular function in both eyes, and establishing intact stereopsis, becoming a person with good visual function. This is the highest purpose of strabismus treatment. Cosmetic cure: To improve the quality of life, older patients should also be treated aggressively. Elimination of diplopia: In adults with paralytic strabismus, diplopia can be eliminated and binocular monovision restored by or other treatments. Relief of visual fatigue improves or restores normal head position, etc. Treatment of strabismus Because of the different causes and types of strabismus, the treatment methods are different. Some strabismus is related to hyperopia and astigmatism, and the strabismus can disappear completely or be reduced with the experience of wearing glasses. There are also some strabismus that do not have obvious hyperopia or astigmatism, and wearing glasses will not help to correct the eye position, then surgery should be performed in time to correct it. If the strabismus has amblyopia, the amblyopia should be treated first, and surgery should be done when the vision of both eyes is balanced, which can consolidate the effect of surgery and keep the position of both eyes normal, which is more conducive to the recovery of visual function.