November 1, 2012 
Eye can run towards the nose (convergent) or outward (divergent strabismus). There are also rarer forms of vertical deflection of the eye where the eye runs up or down, and other various combinations of deflection…
Strabismus (squinting) is a disorder of the motility of the eyes. Proper development of eyes and visual pathways develops binocular vision (vision with two eyes) where viewing with both eyes must be coordinated in order for two slightly different images to combine into one and create a full third image (stereovision). If visual acuity is not good or eyes are not looking at the same axle and not moving together, the normal development of the stereovision will not be possible. The eye runs about 6 muscles (upper and lower flat muscles, external and internal straight muscles, and two sideway muscles). The eye may run towards the nose (convergence) or outward (divergent strabismus), and there are also rarer forms of vertical deflection of the eye where eyes run up or down, and other possible combinations of the deviation. In cases where the movements of both eyes are not aligned, whether one eye lags behind when starting to move or is already not set straight in its primary position (looking straight ahead), it is necessary to perform the operation of strabismus.
The strabismus surgery includes operating on the external eye muscles in order to change their strength and sometimes direction of action, and in that way put the eye in the corresponding regular position. This is achieved by weakening or strengthening a particular muscle based on preoperative measurements, squinting type, age of the patient, a goal that one wants to achieve with the operation.
Operations of muscle weakening are retroposition (scroll back the muscle vertex) and myotomia (releasing the part of the muscle to weaken the strength). Surgeries of strengthening the muscles are resection (cutting out a certain part of the muscle to shorten it and thereby reinforce the action) and anteposition (moving the muscle vertex forward).
Although the external eye muscles move the eye, the position of the eyes is determined and controlled by the brain, so the operation will not automatically change the signals the brain sends to the muscles. It is necessary to combine the operation with other methods of treatment (treating amblyopia by wearing appropriate visual aid or periodic closing of certain eye, muscle exercises exercises c of entral vision or fusion).
Taken from: www.jutarnji.hr