If congenital internal strabismus is detected in newborns born within 6 months of age, the best time for strabismus surgery is before monovision develops in both eyes, usually around the age of 3 years. If the infant is found to have internal strabismus after 6 months of age, immediate strabismus surgery is usually not recommended. Surgery. For infants and children with strabismus who have been treated with glasses for more than 6 months and whose strabismus symptoms have not improved or have only decreased, it is generally recommended that strabismus surgery be performed as soon as possible. For patients with monocular strabismus, in order to more favorably restore the patient’s binocular monovision function, masking therapy can be used in the early stage, and if the masking therapy does not significantly improve the strabismus symptoms after six months, strabismus surgery can be considered at this time.