Strabismus

By the age of 3 to 4 months, an infant’s eyes should be able to focus on small objects, and the eyes should be straight and well-aligned. A 6-month-old infant should be able to focus on objects both near and far.

Strabismus usually appears in infants and young children, and most often by the time a child is 3 years old. However, older children and even adults can develop strabismus. The sudden appearance of strabismus, especially with double vision, in an older child or adult could indicate a more serious neurologic disorder. If this happens, call your ophthalmologist immediately.

A condition called pseudostrabismus (false strabismus) can make it appear that a baby has crossed eyes when in fact the eyes are aiming in the same direction. Pseudostrabismus can be caused by extra skin covering the inner corners of the eyes and/or a flat nasal bridge.

Anyone older than four months of age the agewho appears to have strabismus should undergo a full ophthalmological examination by a pediatric ophthalmologist, with extra time spent examining how the eyes focus and move.  The examination may include the following:

• Patient history (to determine the symptoms the patient is having, family history, general health problems, medications used and any other possible causes of symptoms)
• Visual acuity (reading letters from an eye chart or examining the visual behavior of young children)
• Refraction (checking the eyes with a series of corrective lenses to measure how they focus light).
• Alignment and focus tests
• Examination after dilation of the pupils to determine the health of internal eye structures

Treatment options include the following:

• Eyeglasses or contact lenses: They are used in patients with uncorrected refractive errors. With corrective lenses, the eyes will need less effort to focus and may remain straight.
• Prismatic lenses: Special lenses that can bend the light entering the eye and help reduce the amount of turning the eye must do to look at objects.
• Orthopticexercises (eye exercises): May work on certain types of strabismus, especially in convergence insufficiency (a form of exotropia).
• Medications: Eye drops or ointments. Also, injections of botulin toxin type A (such as Botox) can weaken an overactive eye muscle. These treatments may be used with ,or in place of surgery, depending on the patient’s situation.
• Patching: To treat amblyopia (lazy eye), if the patient has it simultaneously with strabismus.
• Eye muscle surgery: Surgery changes the length or position of the eye muscles so that the eyes are properly aligned. This is performed under general anesthesia with dissolvable sutures. Sometimes strabismus surgery with adjustable sutures is offered to adults, where the eye muscle positions are adjusted after the surgery.

Some believe that children will overcome strabismus or that it will improve on its own. In fact, it can get worse if not treated.

If the eyes are not properly aligned, the following may result:

• Amblyopia (lazy eye) or permanent poor eyesight in the eye with strabismus. When the eyes are looking in different directions, the brain receives two images. To avoid double vision, the brain can ignore the image from the turned eye, resulting in poor development of vision in this eye.
• Blurry vision, which can affect performance in school and at work and enjoyment of hobbies and leisure activities
• Eye strain
• Fatigue
• Headaches
• Double vision
• Poor three-dimensional (3-D) vision
• Low self-esteem (from embarrassment about its appearance)

It is also possible that by not diagnosing strabismus, a serious problem (such as a brain tumor that causes the condition) can be overlooked.

The patient will need to see the Paediatric Ophthalmologist for follow-up to see if the patient has responded to treatments, and to make adjustments, if necessary.

In the case of children with strabismus, if the condition is caught in time and properly treated, it can result in excellent vision and depth perception and can protect against loss of vision.