Pediatric strabismus before surgery need to do the degree of strabismus and binocular visual function examination; but also to carry out routine examination inside the eye, mainly to see whether the child has congenital lesions, such as congenital cataract or fundus lesions; in addition to checking the visual acuity, you must dilate the pupil optometry to see whether the development of visual acuity is the same in both eyes, refractive error or not, whether to wear a lens to correct the first. In the hospital, in addition to dilated optometry, other tests can be done in one day. Dilated pupils are needed for the optometry examination. Older children (usually older than 8 years old) can have their pupils dilated quickly, so that they can be examined on the same day, and their original vision will be restored soon after dilation, without delaying the surgery. Smaller children must use atropine to dilate the pupil slowly, need to drop the drug three to five days before the light examination, the effect of the drug will usually last about a month, the child will have a fear of light performance, can be recovered after a month. Therefore, if it is determined that the operation can be performed through atropine pupil dilation, it is also necessary to wait for one month before the pupil is restored. In addition, because the surgery requires general anesthesia, it is necessary to complete a full body examination in the outpatient clinic to rule out contraindications to general anesthesia, usually including electrocardiogram, chest X-ray and blood tests. After all these tests are done and it is determined that no disease affecting general anesthesia surgery exists, the surgery can be booked. Parents should be aware that before the surgery, try to avoid the child cold, fever, diarrhea and other infectious diseases, etc., so as not to increase the risk of anesthesia.