The exact cause of squint is not known. Six muscles control the movement of each eye. Each of these muscle acts along with its fellow in the other eye to keep both the eyes aligned properly. A loss of coordination between the muscles of the two eyes leads to misalignment Refractive error -hypermetropia (far sightedness) or an eye muscle paralysis may lead to deviation of the eye. Poor vision in an eye because of some other eye disease like cataract, etc. may also cause the eye to deviate. Any trauma or injury to eye can lead to squinting of eyes. Therefore it is important in all the cases of squint, especially in children, to have a thorough eye checkup to rule out any other cause of loss of vision.