Have you ever noticed someone’s eye darting off a different direction, even though they appear to be looking at you? Over the past month, I have seen more than 10 cases where parents report “eyes crossing”, “one eye turning in”, or “one turning out.” Seeing, hearing, touching, tasting, and smelling are very important for all human beings. Something can go wrong with any one of these senses. Vision is a crucial part of development for every child; however there are times when eyes do not work like they should. This is known as amblyopia.
Amblyopia affects 2-5 out of every 100 children and is the most common cause of childhood visual impairment. The American Academy of Pediatrics (AAP) recommends vision screening starting at 4 years of age to detect amblyopia early and allow successful treatment. Children reach visual maturity by 8 years old; the earlier poor vision is diagnosed and treated, the better chances are to avoid permanent vision loss.
Children with amblyopia receive faulty images from the affected eye and their brain cannot “read” what they are visualizing. Three main causes of amblyopia are strabismic, deprivational, and refractive. The first is caused by eye misalignment: eyes can cross in (esotropia) or out (exotropia). A brain will ignore, or “turn off” the eye that is not straight and vision loss results.
The second type develops when cataracts “deprive” an infant’s eyes of visual experience. Left untreated, their brains receive no visual input, then the eyes are unable to communicate with the brain resulting in permanent vision loss. The “critical period” for visual interpretation in humans is birth to two years of age.
The third type occurs when severe far-sightedness, near-sightedness, or astigmatism (blurry vision) are present. The brain realizes it is receiving ‘false’ information so it ignores the unclear images, resulting in vision loss in one or both eyes. These difficulties may be invisible to parents, teachers, and even pediatricians because children cannot report blurry vision. This kind of amblyopia in children is difficult to detect and may not be found until a child has a vision test.
Treatment of amblyopia is consistent use of glasses or contact lenses over a long period of time. Ideally, glasses should be worn from sun up until sundown. The brain will learn to trust the corrected images it is receiving. If glasses alone do not improve sight, then patching the “good eye” forces the brain to pay attention to the images of the weaker eye so vision becomes stronger. This is done through eye patches, eye drops, or a combination of the two. For parents, enforcing the use of glasses or an eye patch can be challenging, however kids usually adapt after an initial adjustment period once glasses become part of them.
The best outcome is achieved if treatment is started before age 8, however research has shown that children older than age 12 and some adults can show improvement in the affected eye. Children from 9 to 11 who wore an eye patch and performed vision therapy were four times more likely to show improvement than children with amblyopia who did not receive treatment. A recent National Institutes of Health (NIH) study confirmed that SOME improvement in vision can even be attained with vision therapy in younger teenagers (through age 14).
If all the above do not correct the problem, eye muscle surgery involving loosening or tightening the muscles causing the eye to wander can be an option. Although it is an invasive measure, surgery is considered safe and effective and usually does not require an overnight hospital stay.
Everything we do in our daily lives involves reading. Vision is extremely important to help a child function independently as an adult in society. If you think your infant or child has crossing eyes, especially when they are tired, listen to your instinct and schedule an appointment with your pediatrician. When amblyopia is overlooked a child loses optimal vision; they will struggle more than others around them for their entire lives.