Under normal circumstances, the visual axes of both eyes should remain parallel when gazing at distant objects, and the movements of the two eyes should be coordinated and balanced to maintain eye position through the fusion function of both eyes so that they can keep gazing at the same target. When the position or movement of the eyes is abnormal causing the visual axis of both eyes to be separated and unable to look at the same target, it is called strabismus, such as one eye is biased to the nasal or temporal side, or one is high and one is low. The prevalence of strabismus is 2.7~7.2% in foreign countries and 1~1.5% in China. Common internal strabismus is a type of common strabismus in which the visual axis of one eye is skewed to the nasal side due to non-paralytic factors, and is the most common type of strabismus in children. Since common strabismus occurs early in life, the development of visual function is still immature, so it not only affects aesthetics, but also leads to monocular amblyopia and bilateral monocular dysfunction, which affects the establishment of stereo vision and has an impact on school and adult career selection, life, and family organization, so early detection and treatment are necessary. Further, treatment of strabismus in children is not cosmetic surgery and has therapeutic implications for promoting normal visual development and correcting amblyopia. Childhood internal strabismus needs to be differentiated from canthus, kappa angle, eyelid deformity, and abnormal eye spacing, with canthus being the most common form of pseudo-intraocular strabismus. The earlier the strabismus is treated, the better. Only early treatment during visual development can prevent amblyopia and enable early cure of existing amblyopia. Refractive correction is very important for common internal strabismus, and a significant proportion of common internal strabismus formation is related to failure to correct hyperopia in time. The basis of refractive correction is a regular dilated eye examination, and children under 12 years old are recommended to use atropine to dilate their pupils in order to fully eliminate accommodation. For correction of hyperopia, it is important to wear adequate corrective glasses in the early stage, maintain the glasses for more than 3 months, and adjust the prescription of the glasses according to the improvement of the eye position or undergo surgery under the guidance of a professional physician. The indications for surgery are non-adjusted internal strabismus. For partially regulated internal strabismus, surgery can only correct the remaining strabismus after strict lens wear. Adjustment strabismus is not suitable for surgery. Timing of surgery: 1. Children with amblyopia should first be treated for amblyopia to achieve normal or near normal visual acuity and balanced visual acuity in both eyes. 2. Patients with hyperopic refractive error should wear glasses strictly for more than 3 months to make the adjustment completely relaxed and the strabismus degree stable before surgery. 3.Children with the above conditions should have early surgical correction, which is beneficial to the overall formation of visual function and physical development. The timing of surgery should not be delayed due to fear of anesthesia and other problems. The surgery should be performed under general or local anesthesia. Experienced surgeons can design the surgical volume well according to the degree of strabismus from the preoperative examination and do not need to adjust it intraoperatively. Therefore, routine surgery can be performed under general anesthesia, which eliminates the pain and the fear brought by the local anesthesia patients who can see part of the surgical procedure, making the surgery with a high safety level. Some cases of complex surgery and multiple surgeries can be performed under local anesthesia for patients who are able to cooperate due to the decreased predictability of the surgical outcome, so that intraoperative adjustments can be made to the surgical volume. However, it is important to be clear that intraoperative adjustments have limitations, and intraoperative eye position can be highly inaccurate and lack reliability due to interference from pain, tension, and other factors. Because strabismus surgery operates only on the surface of the eye without destroying the integrity of the eye and without making an incision in the eyelid skin, the surgery is safer if the patient maintains good stability intraoperatively. The common strabismus is characterized by the same degree of strabismus when both eyes are gazed at separately. The surgical design is based on the results of the strabismus examination and can be performed in either eye or in both eyes, not necessarily in the eye with episcleral strabismus. Factors affecting the effect of surgery: 1. Irregular refractive correction, wearing glasses is not strict. 2, the accuracy of the examination is not good: such as the patient is young, the examination is not cooperative; strabismus degree changes a lot, may not have all the performance during the examination, etc. 3, the patient’s extraocular muscles and innervated nerves are more variable than normal. 4.The position and function of the extraocular muscles of reoperative patients have changed and cannot conform to the conventional surgical design amount. 5.The visual acuity of both eyes is disparate, lacking binocular monocular function.