Children’s eyes are short and all have physiological hyperopia. Since the child’s need to look at near objects gradually increases after the age of 2, and the children’s eyes have strong regulation and good contraction of the extraocular muscles, if they have the habit of looking at things too close from childhood, so that both eyes often maintain a high degree of regulation, which is inevitably accompanied by too much turning of both eyeballs inward, this is most likely to cause internal strabismus. In addition, congenital factors and birth injuries, and poorly developed visual function can also cause it. There are many reasons why strabismus occurs in children, and different causes cause different types of strabismus. 1. Common causes of common strabismus: 1. congenital abnormalities in the development of extraocular muscles, resulting in an imbalance in the strength of the extraocular muscles, leading to a skewed eye position. 2, refractive adjustment factors, such as hyperopic refractive error, due to excessive regulation caused by the regulatory collection, triggering the internal strabismus; such as obvious myopia, due to the non-use or less use of regulation, resulting in convergence deficiency, due to the start of exotropia. 3.Regulatory convergence and regulation imbalance, such as high AC/A type collection over-intensity type of internal strabismus. 4, congenital or acquired visual perception disorders, such as congenital cataract, optic nerve development abnormalities, corneal leukoplakia, etc. cause low vision or complete loss of vision, resulting in the fusion function of both eyes cannot be established normally, causing eye position deviation, also known as perceptual internal strabismus or perceptual exotropia. 5. Genetic factors. 2. Common causes of non-common strabismus: 1. Congenital developmental abnormalities, including abnormal development of the central nervous system, nuclei innervating the extraocular muscles or peripheral nerves, such as extensive fibrosis of the extraocular muscles, retrobulbar syndrome and other congenital cranial nerve abnormalities innervation syndromes. Such diseases belong to hereditary diseases. 2, birth injury during childbirth, which causes pressure on the head or orbit, resulting in nerve and muscle damage, causing extraocular muscle paralysis. 3. Intracranial or systemic diseases during infancy and childhood, such as encephalitis, meningitis, systemic infections or immune diseases, intracranial occupational diseases, etc., secondary to ocular deviation. In terms of treatment, first of all, the cause should be clarified, except for malignant lesions; the pupil should be dilated, refractive error should be corrected, and amblyopia should be treated. After that, strabismus in children should be treated as early as possible. Different types of strabismus have different ages of onset, and the best time for surgery is also different. The general principle is: the earlier the onset of strabismus, the earlier the surgery should be performed; the poorer the control of eye position, the earlier the surgery should be performed; and the more distorted the visualization, the earlier the surgery should be performed.