Most cases of strabismus in children are of unknown cause.
Squint is caused by a lack of coordination between the eyes, causing the eyes to point in different directions and the eyes do not focus simultaneously on a single point.
Squint results from unequal pulling of muscles on one side of the eye, or a paralysis of the eye muscles.
A family history of the disease
is a known risk factor.
Squint in adults may result from injuries to the orbit or brain, including closed head injuries and strokes.
Persons with diabetes
may suffer with squint due to poor blood supply to the eye muscles.
Loss of vision in one eye from any cause will usually cause the eye to gradually turn outward.
Another common cause of strabismus is farsightedness (hyperopia) which may cause the eyes to turn inwards (crossed-eyes).
Rarely, squint may be due to cataract or a serious condition like a tumour.