It is important that an early diagnosis be made so that treatment can be instituted immediately. The doctors evaluate the patient on different modalities of vision like visual acuity, depth perception and alignment. The treatments instituted largely depend on the type and the severity of the problem.
Corrective Lens (specs): Sometimes the squint is caused due to voluntary movements of the eye to compensate for the inability to see clearly. Prescribing a corrective lens can help get rid of the problem.
Patching: In this method a patch is applied over the "good eye" thus making the "bad eye" work more and over time correcting its deficit.
Surgery: The muscles attached to it move the eyeball. When they malfunction, it may lead to a squint. In this case you have two options. One, to take the affected muscle and change its attachment so that its action produces the right movements. Second, surgically remove the extra muscle and thus aligning the muscle with its counterpart.