Eye muscle surgery is also known as strabismus surgery. This type of surgery can be performed to treat any type of ocular misalignment such as esotropia, exotropia, or hypertropia. The goal of surgery is typically to improve binocularity in children and help resolve diplopia (double vision) in adults. What surgery to perform is dependent on the type of misalignment and the severity of the misalignment.
Source: EyeWiki