Crossed or deviated eyes are called strabismus. This condition can occur from birth in children or later in adulthood. In children, strabismus is often caused by excessive farsightedness and can be treated with glasses. All cases of strabismus can cause double vision and may be treated with glasses with prism correction or require surgery to straighten the eye. Other causes of strabismus include stroke, diabetes or other neurological disorders. If strabismus is not treated at an early age, amblyopia, or a lazy eye may occur which can decrease vision permanently. Contact an optometrist or ophthalmologist in your area for more information.