Squint is a misalignment of the two eyes so that both the eyes are not looking in the same direction. This misalignment may be constant, being present throughout the day, or it may appear sometimes and the rest of the time the eyes may be straight. It is a common condition among children. It may also occur in adults. 

The exact cause of squint is not really known. The movement of each eye is controlled by six muscles. Each of these muscles acts along with its counterpart 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.