Strabismus and amblyopia

Strabismus describes the misalignment of the eyes where they appear to turn out, turn in, or one eye may look higher than the other.  Strabismus is a fairly common condition and affects 4% of children.  The exact cause of strabismus is not fully understood, but heredity may play a role.

It is important to understand that children do not outgrow strabismus, and it is never too early to have a child’s eyes examined.  If you even suspect that a child’s eye is misaligned, an exam by an eye doctor is indicated to determine the cause and to begin treatment.  All children should be screened for strabismus by the family doctor, pediatrician or eye doctor during infancy, particularly when there is a family history of strabismus.  We also believe all children should be examined by an optometrist or ophthalmologist during preschool.  If the exam is delayed until the child starts elementary school, it may be too late to fully correct the strabismus or amblyopia.

Treatment of strabismus is important to prevent reduced vision (amblyopia) and to promote binocular vision, which helps eyes to work together and transmit one clear image to the brain.  Treatment may include glasses, patching and/or surgery.  As a rule, the earlier amblyopia and strabismus are treated, the better the visual result.

Amblyopia, also known as “lazy eye”, is a condition in which the brain favors one eye over the other because one eye has a significantly better ability to focus on objects than the other eye.  This condition is the most common cause of visual problems in young children.  Symptoms include crossed eyes, farsightedness and nearsightedness.

Amblyopia can be corrected until around age eight, when the child’s brain may be irrevocably conditioned to ignore the images captured by the lazy eye.

The traditional treatment for amblyopia is to have children wear a patch over the “good” eye to force the “lazy” eye to work on focusing and transmitting images to the brain.  A study by the National Eye Institute showed that eye drops are another effective treatment for pediatric amblyopia.  After six months of treatment, researchers found that the drug Atropine, when placed in the good eye, worked almost as well as patching.  Atropine works by temporarily blurring the vision in the good eye, forcing the lazy eye to take over the work of seeing.  The researchers reported that the patch was 79% effective in treating amblyopia compared to 74% for Atropine drops.

We still prefer patching to Atropine drops unless the child (and parents) cannot comply with the patching regimen.  For many of my pediatric patients, ‘round-the-clock’ patching is not required, so they may go without a patch during school hours or a few hours each night.  With atropine, however, the vision in the good eye will be blurry for up to a week, so the child doesn’t have a chance to take a brief daily respite from the therapy.  In addition, some children are allergic to Atropine and, from our experience, patching provides faster results if the patch is used as prescribed.

If patching or eye drops are not effective in correcting amblyopia, your child’s ophthalmologist may recommend strabismus surgery.  During this outpatient surgery, generally performed by Dr. Kathryn Hodges at Omaha’s Children’s Hospital and Medical Center, the eye muscles are adjusted that the mis-aligned eye is positioned correctly.  The ‘good’ eye may be patched after surgery so that the lazy eye begins to function correctly.

The animation below provides an overview of strabismus and it’s symptoms.

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