Crossed eyes or strabismus can occur all of the time or just be an intermittent symptom. It occurs when the eyes do not turn or align properly when trying to focus on an object. It is most commonly diagnosed in children, although adults can get it too. The first step in treatment is to determine the cause of crossed eye. In many cases glasses and exercises to strengthen the eye muscles can help to correct the problem.
Abnormal Brain Signals
Cross eyes can occur due to a miscommunication between the brain and the muscles that control eye movement. The eye muscles are unable to coordinate eye movements in both eyes at the same time. Why this happens in some and not others is not well understood, according to the American Association for Pediatric Ophthalmology and Strabismus. This condition can occur in healthy children and the cause may never be known. Eye exercises, glasses and in some cases surgery may be required to correct the problem. This is important because over time the brain may ignore signals from one of the eyes to compensate. This can lead to chronic vision problems.
Trauma and Disease
According to the University of Iowa, this condition can be present at birth due to tight eye muscles, which can be corrected with surgery. Farsightedness is a common trigger in children age 2 to 6. This condition tends to run in the family and it can occur secondary to conditions such as cerebral palsy, Down syndrome and hydrocephalus which is a build up of fluid in the brain. In addition, any injuries to the head that damage the eye muscles, eye nerves or other structures in the eye can contribute to cross eye.
Medical Conditions
A stroke can damage cells and nerves in the brain that control vision which can contribute to cross eye. Cross eye can also occur due to a brain tumor or any condition that causes swelling and pressure in the brain, according to the University of Virginia Health System. Medical conditions such as diabetes, high blood pressure and thyroid conditions that can cause nerve damage, are other triggers if not well controlled. If vision is lost in one eye, that eye may eventually turn in. Developing cataracts in one or both eyes may also contribute to strabismus.
