Can 'Lazy Eye' Be Reversed in Older Children?

Have you heard the word amblyopia before?

Amblyopia, commonly called 'lazy eye', is a healthy eye with poor eyesight. The eyeball itself is not the problem, rather, the brain's receptive fields recognize a difference in the visual quality between the two eyes. In young children the brain will not tolerate this difference and so it indiscriminately disregards the visual input from the weaker side. In time the vision in the affected eye gets weaker and weaker.

How does the brain know which side is 'weaker'?

• If there is a significant refractive error in only one eye then the uncorrected eye will be blurrier...and soon amblyopic.
• If a child has congenital cataract in one eye (cloudy lens) the brain will preferentially process visual images only from the noncataractous eye.
• If one eye is crooked so that it cannot fixate on a central target the brain will also ignore its wayward images.

Quickly fix the problem (eye muscle surgery, cataract removal, spectacle correction) and the weaker eye can be rehabilitated by temporarily patching the stronger eye. For some children atropine eyedrops work as well as patching.

Here's the wrinkle: Amblyopia therapy works best when begun in early childhood. By age 5 the visual pathways are mature. By age 8 it is near impossible to reverse 'lazy eye'. Until now.

It has now been shown that for a select group of amblyopic children, those whose 'lazy eye' was due to marked astigmatism in only one eye, a favorable response to amblyopia treatment continues after age 8. The traditional deadline may not apply.

Vision researchers from the University of Arizona followed nearly 500 children between ages 5 and 13. Visual recovery after one year of patch therapy was insignificant in most older children except for those with marked astigmatism. Older children responded as well as patients half their age. This was an unexpected finding.

Here are a few cautions: Only a minority of amblyopia is attributed to marked astigmatism in only one eye. 'Lazy eye' due to crooked eyes or farsightedness did not improve in older children. Most school-age children would find it extremely difficult to tolerate daytime patching, especially among their fellow students. In the earliest stages of treatment, patching the stronger eye leaves the child with a very blurry, uncomfortable world. Treatment failures are common because the child is unwilling to comply with the rigorous patching schedule.

Now the upside: If it is now possible to reverse traditional teaching and correct this particular type of amblyopia, hope remains strong that researchers can discover new ways to help millions of other children recover useful eyesight in their 'lazy' eye.

REFERENCE: Harvey EM. Optical Treatment of Amblyopia in Astigmatic Children. Ophthalmology 2007; 114:2293-2301.

Related Topics:

• WebMD Video: Lazy Eye Treatment - Hope For Older Kids
• How to Help Your Child Wear an Eye Patch

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