1, what is strabismus strabismus is the two eyes are not parallel, when one eye gaze, the other deviates from the direction of gaze, and this deviation is not fusion function can control, overcome, the patient does not have two eyes monocular vision. 2, the etiology of strabismus Strabismus can be congenital or can be formed later in life. The congenital ones often appear at birth or within 6 months after birth; the acquired ones are formed by many factors, such as trauma or other diseases affecting the eye meridian and eye muscles; visual impairment or binocular refractive disorder (hyperopia/myopia) occurring in infancy and childhood, etc., which can cause strabismus. Strabismus can occur at any age, but most of the strabismus related to refractive factors occurs in preschool. 3, the harm of strabismus Obvious strabismus will affect the appearance, which is often the main reason for patients to seek medical attention; strabismic children often feel that their eyes have aesthetic defects, reluctant to look at each other, lack of self-confidence, which seriously affects the psychological development and social skills of children. In addition, strabismus often has a compensatory head position and causes head tilting. Amblyopia Most patients with strabismus have amblyopia at the same time. Due to the long-term gaze of one eye, the other eye will cause disuse vision loss or stop development, causing amblyopia. Stereopsis affects the visual function of both eyes, and in severe cases there is no good stereopsis. Stereopsis is a prerequisite for people to do fine work. If there is no good stereo vision, it will be greatly restricted in learning and employment. 4, the classification of strabismus at any time are manifested strabismus phenomenon is called dominant strabismus; some strabismus is in a certain situation to appear, especially in fatigue, inattention or discomfort will appear, called intermittent strabismus. (1) Horizontal strabismus: It can be divided into. Internal strabismus: the strabismic eye is skewed to the side of the nasal bridge, commonly known as “cross-eyed”; external strabismus: the strabismic eye is skewed outward. (2) Vertical strabismus: one eye is higher than the other. 5, strabismus treatment For strabismus, except for the adjustment of internal strabismus can wear glasses to correct, the other can only be treated by surgery. Strabismus surgery is currently a relatively mature technology. Since the surgery is performed outside the eye, it generally does not affect the patient’s vision, but very few patients may have diplopia after the surgery, which usually disappears within one month due to the high plasticity of the visual system in children. Due to individual differences, overcorrection or undercorrection may occur after surgery and require reoperation for adjustment.