New research findings led by Thomas Krahe and Ary S. Ramoa of Virginia Commonwealth University School of Medicine offer two pieces of good news for treating children with amblyopia.
First, the researchers have found evidence that the neural wiring in the brain’s visual system is not dismantled by visual deprivation–for example, due to a cataract–during what is known as the “critical period” of vision development. Rather, the wiring is merely deactivated, capable of being rapidly reactivated when vision is restored.
And secondly, the researchers wrote in an article published in the October 20, 2005, issue of Neuron, their findings suggest that allowing children with amblyopia to use both eyes–rather than patching the stronger eye to encourage use of the weaker one–enables better recovery. Such findings are clinically important because about three percent of people suffer loss of visual acuity in one eye during early development.
The researchers also found that blocking protein synthesis in the brain with drugs did not affect recovery. Such protein synthesis is necessary if neuronal regrowth is required for recovery, indicating that the basic visual wiring had been preserved during deprivation.
In a preview of the paper in the same issue of Neuron, Takao Hensch wrote that “The results reported here are wonderfully harmonious with the rapid improvement in the acuity of human infants upon restoring visual input during the critical period. Adapting these principles may also motivate therapeutic strategies to aid the precise recovery of function in older, well-established circuits once thought to be beyond repair.”