1.What is strabismus? When one eye looks at the target and the other eye’s visual axis deviates from the target, it is called strabismus. Sometimes parents may find that their baby is looking at the object with both eyes, but that is not strabismus, it is generally called side-sightedness, which is mostly due to bad habits or refractive error. Whether it is strabismus or lateral vision, once found, should be promptly to the hospital. 2.Why does strabismus occur? Generally speaking, non-common strabismus can often be examined for obvious causes, while the cause of common strabismus is not yet clear. Most of the strabismus we usually refer to is common strabismus. The causes of common strabismus are multifaceted and may be the result of several factors working together even in the same patient. The most common causes of common strabismus are as follows: (1) Refractive error: Patients with hyperopia who work at close distances for long periods of time and patients with initial presbyopia, because of the need to strengthen the adjustment, produce excessive convergence, which leads to internal strabismus. Patients with nearsightedness, which requires little or no adjustment, will produce insufficient vergence, which may lead to exotropia. (2) Sensory impairment: Due to certain congenital and acquired causes, such as corneal opacity, congenital cataract, vitreous opacity, abnormal macular development, and excessive refractive aberration, the retina is poorly imaged, visual function is low, and both eyes are unable to establish a fusion reflex to maintain ocular balance, thus leading to strabismus. (3) Genetic factors: Since the same family has similar characteristics in eye anatomy and physiology, strabismus caused by anatomical abnormalities may be passed on to the offspring in a polygenic way. 3.What are the adverse consequences of strabismus? 1. The main adverse consequence of strabismus is that it affects the normal binocular vision function and leads to the lack of stereo vision. This can hinder the choice of certain occupations. Children who lack normal visual function are not capable of performing fine operations such as aerospace, aviation, exploration, mapping, driving, drawing, and medical work. 2, strabismus affects the appearance of people, especially in childhood can be due to strabismus and the surrounding students shame, so that their physical and mental shock. This can lead to loneliness and low self-confidence, which can affect the child’s life. In adults, strabismus can seriously affect social activities and career choices. 4.When is the best time to treat strabismus? Generally speaking, if children with common strabismus are not treated in time, they may lose the visual function of both eyes after the age of 12, and even if the strabismus is solved by surgery after this age, it can only have a cosmetic effect. Therefore, strabismus should be treated promptly. However, for children with mild strabismus who cooperate with the examination, the timing of surgery can be decided depending on the function. For the timing of surgery for non-common strabismus, surgery is usually performed six months after the onset of the disease. 5. Timing of surgery for several common strabismus (1) Congenital strabismus must be operated early. The child’s binocular vision is usually formed before the age of 5. If the child is suffering from strabismus during the period of visual development, both eyes cannot look at the same target at the same time, so there is no way to talk about the development of binocular vision, and if it is not corrected in time, eventually the child’s binocular vision will not be developed normally and amblyopia will be formed. (2) The strabismus caused by refractive error should be corrected first, and then the treatment of strabismus should be considered according to the presence of amblyopia. Generally speaking, amblyopia correction is given priority, and surgery for strabismus is performed after basic correction of amblyopia. (3) For intermittent exotropia, if the degree of strabismus is low and the strabismus is usually not visible, the eye position can be observed on the basis of checking the visual function of both eyes. For intermittent exotropia with more frequent episodes, timely surgery is recommended. (4) For children with internal strabismus, if the angle of deviation is small and not easily detected, the development of eye position can be observed depending on the change of the disease. Generally speaking, the internal strabismus of children can be reduced with the growth of age. 6.How should strabismus be treated? Most strabismus is treated by surgery, and some strabismus is treated by wearing glasses. There are even some strabismus that require both glasses and surgery. The blind belief that strabismus will disappear with age is not acceptable. Surgical treatment should only be performed for mild strabismus at a later date by closely monitoring the changes in visual function. Once strabismus is found, you should immediately go to the hospital to see an ophthalmologist to understand the general plan of treatment so as not to delay the best time for treatment. 7.Will strabismus surgery cause vision loss? No. Strabismus surgery is an external eye surgery and does not go inside the eye, so it will not affect the patient’s vision. Even if there is a temporary loss of vision after surgery, it is due to the visual disturbance and conjunctival suture irritation after surgery. 8.Why do strabismus sometimes need to be treated surgically in stages? Generally speaking, for patients with strabismus ≥ 90 trigeminal degrees, due to the large angle of deviation, it is often necessary to perform multiple extraocular muscle surgery. In principle, it is not permissible to operate on three straight muscles in one eye, as this would cause ischemia at the front of the eye. If such large angles and different types of combined strabismus are encountered, they should be explained clearly to the patient, and the surgery can be performed in stages depending on the specific situation. In addition, factors such as the operation of the surgery and the individual differences of the patient can also affect the outcome of the surgery. Therefore, the patient and family should be informed of the possibility of reoperation before surgery. Especially in the case of congenital internal strabismus surgery in young children, it may be necessary to perform the surgery in separate sessions because of the difficulties in determining the degree of strabismus before the surgery due to the lack of cooperation with the examination at a young age. 9. Do children with no strabismus when they wear glasses but obvious strabismus after glasses removal need surgery? No. Complete refractive strabismus cannot be treated surgically. The best treatment for this type of strabismus is to wear optical glasses. Not only is the eye position correct with glasses, but you can also have monocular vision in both eyes. However, some patients or families do not accept glasses and opt for surgery instead. This surgery does not change the refractive adjustment status, and internal strabismus can occur after surgery. In addition, the patient’s poor visual acuity without glasses does not achieve the purpose of removing the glasses. Therefore, this type of patient should not be treated surgically. In partially adjusted internal strabismus, the surgery is designed to address only the non-adjusted portion, while the adjusted portion still needs to be addressed with a lens. It should be clearly explained to the patient and family before surgery that the eye position is correct when wearing glasses after surgery, and there will be a certain degree of strabismus when taking off the glasses. After the surgery, the patient should be re-examined and the prescription of the glasses should be adjusted. Regular review, according to the change of refraction and strabismus degree timely replacement of glasses. 10.Why should I have eye strabismus surgery if my baby has a crooked neck? Most cases of squinting neck are caused by abnormalities in the neck muscles. This abnormal muscle change can often be treated through physical therapy and other therapeutic measures in the early stages, but some patients have to undergo surgery to cure it. However, there are also eye abnormalities that can cause a child’s head to tilt. For children with no significant abnormalities in the neck muscles and a tilted head, oculocutaneous squint should be considered. Oculocerebral tilt is mostly due to congenital paralysis of the eye muscles. The most common type is paralysis of the superior oblique muscle of one or both eyes. When a child adopts this tilted head position, it can alleviate the discomfort due to the strabismus. However, prolonged head tilting can have many negative consequences for the child. First, there is the facial asymmetry caused by the crooked head (squint), which, due to gravity, causes one side of the face to be full and the other side to be thin. Secondly, it is the effect on the bones of the neck, causing scoliosis of the cervical spine. Thirdly, it may also cause developmental deformities of the mandible. Therefore, congenital oculomotor palsy causing squint should be treated with surgery early. 11.Why is there double vision after surgery? After strabismus surgery, a small number of patients may experience diplopia. In most patients, diplopia can disappear on its own within a short period of time, and the fastest can disappear within one to several weeks after surgery. Children have a rapid change in binocular vision and overcome diplopia faster than adults. Postoperative diplopia should be thoroughly explained in adults with strabismus. The amount of correction for this type of strabismus should be such that it does not interfere with daily life. Postoperative diplopia can also occur if the surgery is overcorrected, such as when an exotropia becomes an internal strabismus after surgery, or an internal strabismus becomes an exotropia after surgery. Mild diplopia does not need to be treated, and it can be corrected with trigeminal lenses if necessary, and it can be corrected by surgery again when there is an intolerable diplopia in the front. 12.Anesthesia for strabismus surgery Adult patients who can cooperate with the surgery usually use local anesthesia, which is relatively simple and safe. For strabismus surgery in pediatric patients (generally ≤12 years old), general anesthesia is used, which has certain risks. Parents should follow the doctor’s instructions and cooperate with the child for general examination and preoperative dietary restriction. It is recommended to go to a hospital with strong technical expertise to perform strabismus surgery requiring general anesthesia.