1.What is strabismus? Strabismus is often referred to as “squint” or “crossed eyes”, and as the name implies, it is a misalignment of the eye. In medical terms, it means that the visual axis of the eye is skewed and cannot be overcome by the fusion function of both eyes. The most common forms are internal strabismus, external strabismus, upward strabismus, and downward strabismus. Strabismus can exist all the time, or it can be orthophoria and strabismus at the same time, or only when fatigue, illness, or lack of energy, the former is called constant strabismus, the latter is called intermittent strabismus, and when orthophoria and strabismus alternate regularly is called periodic strabismus, the most common is 48-hour cycle. Shen Qin, Ophthalmology Department, Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine 2. What are the dangers of strabismus? Strabismus affects the appearance, and many people may answer this way, which is also the main motive for most strabismus patients to seek medical treatment. But the harm of strabismus is much more than that. In those who develop strabismus at an early age, it is impossible to have good stereo vision because both eyes do not have the opportunity to work in harmony and the monocular function of both eyes cannot develop normally. Stereo vision is an advanced visual function that only human beings have, and is one of the prerequisites for human beings to engage in various fine jobs, and people who do not have stereo vision will be greatly restricted in learning and employment. On the other hand, patients with strabismus who use one eye for a long period of time will inevitably develop visual impairment in the wasting eye and form amblyopia. Some patients with strabismus often take a compensatory head position such as crooked head and sideways face in order to reduce the interference of diplopia, which happens in childhood and affects physical development, and many sick children have spinal curvature secondary to the lack of timely correction. 3, why some children squint in the sunlight one eye? Often see some children in life, in the room when the eyes are wide open, no different from normal people, and once outdoors, especially in the sun, squinting one eye as if afraid of light. Careless parents do not notice this phenomenon, some careful parents found this situation, but often a hundred checks can not get results. In fact, if you take a flashlight and let your child look at it while covering one eye, you will find an exotropia, which is a common symptom of intermittent exotropia. This kind of strabismus is characterized by being able to be orthotropic when concentrated, and exotropia when fatigued, ill or looking away, often in the morning in an orthotropic position, and easily exotropia in the afternoon, when exotropia suddenly appears can occur when diplopia, so the child instinctively squinted one eye. 4.Is it a disease for children to look at things with a tilted head? Some children are fine when looking at things, but when watching TV or concentrating, they will tilt their heads or turn their faces to the side, no matter how parents correct them, but they cannot correct them, in fact, such children are likely to have eye diseases. When both eyes are not at the same level, that is, when a person has vertical strabismus, he or she often has diplopia. In order to overcome diplopia, children with vertical strabismus often adopt a compensatory head position such as tilting the head, turning the face sideways, lifting the chin or collecting the chin, which is commonly known as squinting the neck. This kind of strabismus caused by strabismus is called oculogyric strabismus. It is different from the strabismus caused by sternocleidomastoid lesions, etc., and can only be eliminated by correcting the strabismus. Although children with vertical strabismus may maintain a certain degree of binocular monocularity due to head position compensation, long-term strabismus can cause asymmetrical facial development and spinal curvature, which affects the health of the child, so the eye position should be corrected as early as possible. Nystagmus is an involuntary oscillation of the eyeball, which can be horizontal, vertical and rotational, with horizontal nystagmus being the most common. Patients with idiopathic nystagmus may have a static nystagmus in one eye, and thus often exhibit a compensatory head position such as a tilted head or sideways face in an attempt to maintain good vision. For this kind of patients, sometimes surgery can help them to eliminate the head position, so if your child often appears to have a crooked head, you’d better take your child to the hospital ophthalmology examination for early detection and early treatment to avoid delaying your child’s condition. 5.Why should I have surgery for congenital strabismus as early as possible? Congenital strabismus generally refers to strabismus that develops within the first year of life, either at birth or after birth, and any strabismus that occurs between birth and one year of age falls into this category. Internal strabismus is the most common. It is one of the worst types of strabismus in terms of prognosis because of its early onset and lack of normal development of monocular function in both eyes. The development of human binocular visual function is gradually matured after birth, and the early stage of development is the key period after birth, so it is during this period that congenital strabismus develops, and the deep inhibition of the development of binocular visual function can be imagined. The only way to correct the eye position before the termination of the developmental period is to operate as early as possible, so that partial peripheral fusion can still be obtained. Many parents are concerned about this reality and feel that their children are too young and want to have surgery when they grow up. They do not know that if the developmental period is missed, it will be difficult to obtain monocular function in both eyes even with extremely coarse periphery even if the eye position is corrected satisfactorily later. Therefore, early surgery is the only option for congenital strabismus. 6.What anesthesia method is used for strabismus surgery in children? Adults and older children can undergo strabismus surgery under local anesthesia or general anesthesia, while younger children have difficulty cooperating with the surgery due to fear of surgery, so only general anesthesia can be used to ensure that the surgery is performed smoothly. 7.Does strabismus surgery have any effect on vision? Most parents of children with strabismus are eager to have surgery as soon as possible to correct the eye position, but they inevitably have some concerns, one of which is whether the surgery will affect their eyesight. There are six extraocular muscles attached to the surface of the eye. These muscles contract or relax in response to excitatory impulses from the brain to maintain the proper position and movement of the eyes. Strabismus surgery is mainly performed on these six extraocular muscles without opening the eye, so there is generally no significant effect on vision. A few people have a mild loss of vision after surgery, mainly because the muscle surgery has produced some pulling effect on the cornea, changing the refractive condition of the cornea, making the original glasses unsuitable, which will recover in the short term. By the same token, strabismus surgery will not improve visual acuity. Some parents have no patience for amblyopia treatment and hope for surgery, thinking that strabismus nursery cures amblyopia at the same time, which is a misunderstanding. Surgery can only correct eye position and provide a basic condition for normal development of vision and binocular monovision, but cannot directly improve vision. 8.Why do I still need to wear glasses after strabismus surgery? Some children need to wear glasses after surgery or other treatments to correct strabismus, which many parents do not understand, and some people take it upon themselves to remove glasses for their children, making the original smooth treatment a twist. Myopia. The children with astigmatism and hyperopia beyond the physiological range need to wear glasses to see clearly and maintain normal vision; some of the children with regulatory strabismus, surgery can only correct the non-regulatory part of the internal strabismus, and the part of the internal strabismus that belongs to the regulation, still need to wear glasses to correct, so these children should also wear glasses after strabismus correction surgery, and regular follow-ups, under the guidance of doctors.