With the same strabismus, why do some children have surgery on one eye and some on both eyes? Why did some choose the right eye and some chose the left eye? The choice between monocular and binocular surgery is mainly related to the size of the strabismus and the type of strabismus: 1, related to the size of the strabismus: when the strabismus is large and the amount of surgery in one eye cannot be solved, binocular surgery is needed; 2, determined by the type of strabismus: for example, convergence deficient exotropia is suitable for monocular Therefore, the same strabismus that can be solved by monocular surgery may also be solved by placing it on both eyes; 3. The choice of eye in monocular surgery: it is mainly based on the dominant eye examination. The dominant eye is the one that dominates in both eyes when we see things and becomes the main burdener in positioning and causing fusion. The surgery should not affect the dominant eye as much as possible, so the operated eye is chosen to be the non-dominant eye; in addition, for perceptual strabismus (disuse strabismus), the surgery should be performed on the eye with poor vision as much as possible. For paralytic strabismus, the degree of strabismus is not consistent from one angle to another. The principle of surgery is to address the strabismus mainly in the direction where the maximum oblique angle is located, based on taking care of the most commonly used eye position in front and below. When paralytic strabismus is present in one eye, the surgeon will perform a measurement of the strabismus in each angle before surgery, and will choose to perform surgery on both eyes or one eye based on the size of the strabismus to be resolved, as well as the postoperative changes in horizontal strabismus, vertical strabismus, and even rotational strabismus, taking into account many factors, and will select the muscle to be treated among the six extraocular muscles to be operated on. Of course, when paralytic strabismus is coexisting in both eyes, most of them should be operated in both eyes.