In neuroscience, the term “plasticity” refers to the ability of the brain to organize itself as the result of the input of both internal (genetic) and external stimuli. Throughout life, this remarkable organ can adapt to changes in visual input to maximize vision potential, whether the eye is a perfectly healthy child’s eye, or an injured adult eye. There is general agreement that young children, with a normally developing brain, properly formed nerve pathways, and a good blood supply have a remarkable ability to develop and utilize visual stimuli. The development of binocular vision is dependent on access to external visual cues that stimulate that development. In many cases, it is a breakdown in the transmission or interpretation of there cues that result in the development of amblyopia or “lazy eye.”
A classic definition of amblyopia is a loss of vision due to no apparent physical defect or lack of use. It is generally believed that when one eye is deprived of adequate visual stimulation, its development lags behind that of the other, more dominant eye. When confronted with a “blurry” image from the affected eye and a clear image from the stronger or dominant eye, the brain may choose to simply ignore or suppress the blurry image completely.
A common cause of blurry vision for a child is refractive error. Anisometropia, a significant difference in refractive status between the eyes, will cause the brain to suppress the blurred image. If a child has uncorrected astigmatism, hyperopia or myopia amblyopia will occur. Early intervention with proper correction will allow the visual pathways and brain to development normally.
Another potential cause of amblyopia is the misalignment of the eyes or “strabismus.” Strabismus is generally defined as a misalignment of the visual axes of the two eyes causing the eyes to appear to be nonparallel. The position of the eyes might present as one eye turning outward (divergent strabismus or one eye turning inward (converging strabismus). The most common treatment for mild or moderate strabismus is to patch the stronger or “dominant” eye, forcing the weaker, amblyopic eye to perform the required visual tasks. In some cases, Atropine drops are used in the dominant eye instead of a physical patch.