Strabismus

Introduction

Strabismus is a condition of visual impairment in which both eyes do not see the same item at the same time. Most commonly begins in early childhood. This condition is also known as crossed eyes.

What causes strabismus?

The reason for the occurrence of strabismus in childhood is unknown, although it is considered that family predisposition plays a role. Normally muscles that are close to the eyeballs work synchronously in order both eyes to move in the same direction at the same time. Strabismus occurs when there is a disruption in the operation of the eye muscles and thus insufficient control of eye movements. When they malfunction, the focus of the two eyes is different, thus creating different images of the eye that brain cannot merge. Sometimes strabismus occurs when the eyes compensate for other vision problems. Strabismus in adults may be due to eye damage, damage to blood vessels, muscles or nerves that innervate the eye muscles. Loss of vision, eye or brain tumours, Graves' disease, stroke and various muscle or nerve disorders can be cause of strabismus in adults.

Risk factors that are reason for the occurrence of strabismus in childhood

Positive family history of strabismus

Vision problems like farsightedness

Muscle and nerve disorders (myasthenia gravis, cerebral palsy, multiple sclerosis etc. )

Down's syndrome

Cataracts

tumours in the brain or eyes

Premature birth, injury during childbirth or some disease in newborn

Head injury

Infections also can be a risk factor such as meningitis or measles

etc..

Symptoms

Often visible sign of crossed eyes are when both eyes do not look at the same point in space at the same time. Ignoring or closing one eye to bright sunlight, turning and tilting the head to look at an object are possible signs of crossed eyes. Child with strabismus may complain of blurred vision, eye fatigue and sensitivity to light. Double images often occur early in the occurrence of strabismus.

Diagnosis

Doctor often only with a look in the eyes of the child will say that the child has strabismus, that is often obvious that both eyes does not see the same item at the same time. The doctor can even see the child while observing at some point by covering one eye. This simple test allows the doctor to estimate what eye turns, how much it turns and to what side, and if there are other circumstances to see them. The doctor will also examine whether the child has amblyopia (condition also known as lazy eye), in which one eye is not used enough, and consequently vision centres in the brain does not develop at a normal weight).

Treatment

The most common way to treat strabismus is the use of glasses, followed by treatment of amblyopia (with drug or covering one eye) and surgical treatment of strabismus. The wearing of glasses can correct strabismus when there is little difference between the axes of the eyes. By covering one eye or drugs may improve amblyopia. In its treatment it will help to align the eyes to focus on the same object and smooth to use. In other cases it may be recommended special exercises for eye muscles. Sometimes surgical treatment is the only option to correct strabismus. With operation it changes the length or position of the external eye muscles in order to better align the movement of the eyes.

Do children outgrow strabismus?

Child rarely outgrows strabismus once it is developed. Without treatment strabismus can cause permanent vision problems. If the child does not use uniformly its eyes it may develop amblyopia (lazy eye or reduced eyesight in one eye). Among infant is normal in early days eyes not to be aligned, but after 3-4 months they already have to work synchronously. In some cases the eyes may seem inconsistent because they have extensive root of the nose that creates a false appearance of crossed eyes (pseudo strabismus). An ophthalmologist should examine any child older than 4 months whose eyes do not comply. The review should be performed earlier if there is an obvious problem.