What is intermittent exotropia? It is a type of common exotropia, which is caused by the combination of abnormal innervation of the central nervous system, imbalance in the collection and separation of the eyes, and anatomical and mechanical factors of abnormal development. The general pattern of its change is that the early appearance of occult exotropia is not easily detected, gradually the appearance of intermittent exotropia can be detected by some parents, and finally the development of constant exotropia is more obvious in appearance. Therefore, intermittent exotropia is a transitional state from occult exotropia to permanent exotropia. The characteristics of intermittent exotropia are intermittent, appearing when fatigued and dazed, mostly without conscious symptoms, and some of them have the photophobia phenomenon of preferring to close one eye in the sunlight. In this type of strabismus, the visual function of both eyes is completely lost. This type of strabismus is not closely related to refraction and cannot be eliminated or controlled by glasses; treatment is mainly surgical. In the past, some scholars have tried to control strabismus by collection training in order to avoid surgery, but long-term observation has confirmed that collection or convergence training cannot fundamentally improve the pathogenesis of strabismus, nor can it fundamentally improve binocular visual function; it can only “reduce” the effect of strabismus in the short term, and cannot cure strabismus to avoid surgery. Moreover, the collection training before surgery also affects the effect of surgery, as the collection impulse is strengthened in the early stage, which is prone to overcorrection, and in the distant stage, as the collection is relaxed, which is prone to undercorrection and unstable phenomenon, making the effect of surgery difficult to grasp. When to operate for intermittent exotropia? Most patients with intermittent exotropia have a tendency to progress and get progressively worse and eventually require surgery, but a small number of patients will have no change or even progressive improvement over the years and may not require surgery. Therefore, it is important for doctors to understand the characteristics of intermittent exotropia and to closely monitor the changes in the condition to determine which patients need surgery and when to operate. Once the diagnosis of intermittent exotropia is confirmed, regular follow-ups are needed to monitor the changes in strabismus and the visual function of both eyes, and surgery should be performed promptly if there is clear visual impairment. Surgery for intermittent exotropia should be considered in the context of the patient’s age, the degree of strabismus (size of the strabismus), the frequency of strabismus, and the patient’s binocular visual function status under close observation. The best age for surgery is between four and six years old, before the visual function of both eyes is significantly impaired, in order to protect or restore the impaired visual function. In addition to observing the recovery of strabismus after surgery, it is more important to observe the recovery of visual function, and if the recovery of visual function is poor, visual function training should be performed in time to promote the reconstruction of binocular visual function!