Intermittent exotropia is a kind of strabismus between exotropia and common exotropia, which means that the visual axes are often separated, initially when looking at a distance, and when looking at a distance, the fused scattering amplitude exceeds the fused total collection amplitude, that is, exotropia is produced, and intermittent exotropia is preceded by exotropia. Treatment measures] 1, ciliary muscle paralysis refractive examination Patients with significant refractive error, especially astigmatism and refractive aberration, to ensure a clear retinal image, should be fully corrected; exotropia with myopia, should be fully corrected; exotropia with hyperopia, correction of hyperopia will reduce the regulatory collection, so that the exotropia increases, the need for full or partial correction, depends entirely on the degree of hyperopia, the patient’s age and the AC/A ratio. Usually less than +2,00D infants and children can be left uncorrected, while correction of hyperopia is usually necessary for larger patients to avoid refractive fatigue. The elderly have exotropia with presbyopia, weakened regulation, such as hyperopia, need to be corrected, you can give the minimum number of degrees to facilitate the look closer. 2, negative spherical mirror with negative mirror to correct intermittent exotropia, can be done as a temporary measure, or placed in the upper half of the bifocal mirror, to treat the separation of too strong; or placed in the lower half of the bifocal mirror, to treat the collection of insufficient, stimulate its regulatory collection, control exotropia, this treatment method, should not be advocated, children with this method of treatment, often cause visual fatigue. Recently, it has been proposed that in the early stage of intermittent exotropia, masking is a good non-surgical treatment method, and with this method of treatment, about 40% of the patients with apparent obliquity (looking away) can become occluded. In the early stage of intermittent exotropia, because most of the time it is exotropia, the number of apparent oblique is not much, and the degree of skew is not big, surgery is not advocated. 4.Surgical treatment The most suitable age for intermittent exotropia surgery is still debated. Jampolsky advocates delaying surgery for immature infants and young children to avoid overcorrection, using negative spherical lenses to enhance fusion, and alternate masking to prevent inhibition. If the fusion deteriorates rapidly, or if the oblique angle is stable, surgery should be considered. The indications for surgery are determined by the fusion control, the size of the oblique angle and the age of the patient. In the absence of intermittent exotropia, surgery should be performed as soon as possible; in the case of strabismus greater than 20 △, according to Huynh; in the case of strabismus greater than 15 △, according to Jampolsky; in the case of strabismus greater than 20 △, according to Hiles; in the case of strabismus with a significant component of apparent obliquity and visual loss of compensation. From the viewpoint of the effect of surgery on retinal correspondence, in order to eliminate the interference of diplopia and confusion, abnormal retinal correspondence and suppression can occur in intermittent exotropia, and the best time for surgery is to eliminate exotropia surgically before it develops into suppression and abnormal retinal correspondence. The results of Yu Gang’s follow-up of 77 cases of intermittent exotropia showed that the younger the age, the higher the chance of restoring normal binocular vision after surgery, while most adults could not restore normal binocular vision after surgery even if the eye position was corrected. It is not easy to master the best timing of surgery clinically. If the age is too young, the examination is not cooperative and the amount of surgery is not easy to master, which increases the rate of reoperation. Jampolsky’s study of intermittent exotropia, which was performed at different ages, concluded that the earlier the surgery, the more frequent the surgery. It was concluded that the earlier the surgery, the more operations, the higher the reoperation rate and the greater the risk of amblyopia and fusion loss. We believe that for children with progressive intermittent exotropia, those with deviations greater than 20△ and those with more than 50% of the time in the apparent oblique period, the surgical plan can be designed according to the size of their deviations and the masking test, and if the deviation is greater than the nearness after 30 to 45 minutes of masking, the posterior migration of the external rectus muscle can be done bilaterally, and the amount of surgery can be determined according to each physician’s test and method. If the oblique angle of looking near is greater than that of looking far by at least 15△ and less than 55△, posterior migration of external rectus muscle can be done bilaterally or posterior migration of non-dominant eye and tendon amputation surgery. If the exotropia is greater than 55△, three muscles can be done, posterior migration of the external rectus muscle in the main eye and posterior migration-truncated tendon surgery in the non-dominant eye. If the external obliquity is greater than 70△, a bilateral posterior migration-tendon amputation is done. If the strabismus is at least 20% smaller than the first eye position when the patient gazes to the left and right, there is a significant risk of overcorrection, especially for patients whose vision is not yet mature. For patients whose vision is not yet mature, posterior migration of the external rectus muscle should be avoided bilaterally, and if posterior migration-tendon amputation is performed on the non-dominant eye, 1 mm less should be done on each side. children, undercorrection should be advocated because a mild overcorrection to an internal oblique state is more likely to result in monocular gaze syndrome than a mild undercorrection to an external oblique state, and may result in the formation of an inhibitory dark spot, leading to developmental amblyopia. On the contrary, if the patient’s visual acuity has developed, a mild overcorrection of 10 to 20 △ is ideal, and it will eventually produce stable results. Overcorrection at 25Δ should be avoided even in visually mature patients, as such overcorrection can lead to blind spot syndrome and prevent postoperative fusion. If the patient has the A or V sign, which is caused by the overfunctioning of the superior or inferior oblique muscle, the horizontal strabismus surgery can be done at the same time as the intramuscular weakening of the overfunctioning muscle, and if both the superior and inferior obliques are overfunctioning, weakening of either oblique muscle is contraindicated. 5, the treatment of overcorrection There are reports that the prevalence of overcorrection in external oblique surgery is between 6% and 20%. Immediately after external oblique surgery, a large degree of overcorrection occurs, and the patient should be operated again within 24 hours because of the possibility of muscle loss or slippage, and the external rectus muscle is less likely to be lost compared to the internal rectus muscle. Significant overcorrection can also occur if the mechanical factor internal rectus muscle has an excessive amount of tendon amputation, but the amount of overcorrection is not as large as the former. The internal oblique is common and can wait for observation, and can disappear completely when the internal oblique is 10 to 15△ after surgery. The small amount of overcorrection after exotropia also depends on the age of the patient. Children with immature vision who have a small amount of overcorrection should be carefully monitored for the development of inhibited dark spot and developmental amblyopia. If the patient does not have a tendency to gaze, alternate masking is feasible, and if there is a moderate tendency to gaze, masking therapy is feasible. In addition, further optometry should be performed. If there is hyperopia, full correction should be applied, and if there is a large near skew, treatment with pupil reduction agents or bifocal lenses should be applied. After the above treatment for 4 months, vision has not done much small amount, to treat a new patient, can not simply restore the previous exotropia surgery. It is ideal to overcorrect 20△ for vision maturity sufferers and still have 20△ internal obliquity 6 weeks after surgery, 2 surgeries are feasible and the surgery should be performed 6 months after the first surgery. It is important to do the traction test before surgery, if traction is found, the muscle, conjunctiva and fascial capsule should be properly posteriorly migrated. 6.The treatment of undercorrection The residual large degree exotropia greater than 15～20△ after surgery can be operated twice within 6～8 weeks after the first operation, and this situation should be considered as a new case. If the residual exotropia is equal to the near exotropia and the first operation is posterior migration – tendon amputation, the same operation can be performed on the other eye; if the first operation is bilateral posterior migration of the external rectus muscle, marginal myotomy of the external rectus muscle on one side combined with tendon amputation of the internal rectus muscle on the same side can be done. If the residual external oblique angle is greater than the proximal oblique angle, the first operation should be posterior migration of the external rectus muscle or marginal myotomy of the external rectus muscle; if the first operation is posterior migration – tendon osteotomy, posterior migration of the external rectus muscle can be done on the other eye. When the second surgery of the external rectus muscle is done, it is better to posteriorly migrate the temporal bulbar conjunctiva at the same time in order to prevent the scar from moving forward and counteracting the surgical effect. For patients with mild undercorrection, the residual obliquity is less than 15 to 18△, and they can be trained with de-suppression and fusion set to achieve a stealth oblique state. If the patient is myopic, all should be corrected. If the patient is orthoptic or hyperopic, ciliary muscle paralyzing agent can be used to stimulate the regulatory collection to make both eyes orthotropic. After obtaining fusion using the above method, the number of drops can be reduced to once every 3 days and continued for 2 months, while using base-to-internal trigeminal lenses with the same degree as the undercorrection, which is effective for patients with mature vision. The number and duration of intermittent exotropia increases as the disease progresses, and finally exotropia can occur when looking at the near. The apparently oblique phase of intermittent exotropia often occurs during fatigue, illness, drowsiness, or inattention. Intermittent exotropia can be temporary in visually immature children with diplopia, which is soon suppressed and has abnormal retinal correspondence. The common symptom is photophobia, and in outdoor daylight, one eye is often closed, the cause of which is unknown. It is estimated that patients look at distant targets outdoors, without near objects to stimulate the collection of both eyes, and bright daylight flashes the retina, interfering with the fusion, and the patient changes from exotropia to obvious, but it is not necessarily certain that such patients close one eye to avoid diplopia. It is possible that the bright light affects the fused pooling of the patient with intermittent exotropia, causing one eye to close. Intermittent exotropia can be combined with the A-V sign, or with other vertical strabismus, such as separated superior strabismus. Auxiliary examination] All strabismus items should be examined, with special attention to the determination of the diagnostic strabismus angle, such as the angle of deflection when looking at a distance, it is best to make the patient look at the target >6m away to fully examine the degree of exotropia and determine the type of exotropia, because the timing of treatment and treatment methods are different. Refractive error should be corrected at the time of measurement to control its adjustment. If the intermittent exotropia is only present when looking at the distance, and the distance oblique angle is greater than the near oblique angle in at least 15△, a masking test should be done, with one eye masked for 30 to 45 minutes, when the masking is removed, the two eyes must remain separated, i.e., when one eye is unmasked, the other eye must be blocked by a universal eye shield, and when opened, the near obliquity should be measured quickly with a trigeminal uniform masking test, and then the far obliquity should be viewed to prevent the patient from having Burian and Franceschetti observed a group of 237 patients with exotropia and only 10 cases were of the separate process type. Thus, it appears that most patients with exotropia look at the distant oblique angle more than the near oblique angle and should be classified as similar to the separated over-strong type. The degree of upward and downward deviation was measured to determine the presence or absence of the A-V sign. Measure the oblique angle when gazing to the left and to the right, whether there is any lateral incomitance (lateral incomitance) problem. By definition, lateral incomitance refers to patients with exotropia, when looking to both sides, the obliquity is 20% smaller than the first eye position obliquity, clinical practice proves that patients with lateral incomitance are easily overcorrected surgically and cause the internal V sign. Check the stereopsis sharp: patients in the occlusion period, must also measure their stereopsis, such as stereopsis is not normal, indicating that the intermittent period of apparent obliquity caused by the decline in stereopsis, within a few months stereopsis continues to decline is a strong indication for surgery to correct intermittent exotropia surgery.