Children with refractive amblyopia often go undetected because their eyes are straight and they don’t have much difficulty with the “activities of daily living.” When told that they need to wear glasses full-time, this is often quite a shock. Add in the need to wear a patch for several hours a day, and not surprisingly, compliance with this treatment protocol is poor. But wearing the lenses and patching is the “backbone” of amblyopia treatment and little or no improvement can be expected if this is not done…… at least that is what “conventional wisdom” has told us to expect. What this traditional approach to amblyopia treatment fails to recognize is that amblyopia is a BRAIN problem and not an eye problem. If a child’s binocular (eye teaming) skills can be improved, this is often accompanied by an increase in visual acuity and other monocular visual skills of the amblyopic eye. In some cases, these improvements also lead to a reduction in the anisometropia (or difference in lens power between the two eyes) and an associated reduction in the lens power required in spectacles to maximize visual acuity. Press and Press have termed this treatment “reverse engineering of hyperopic anisometropic amblyopia.” Everyone is a winner if this can be accomplished. The amblyopia is successfully treated, the need for eyeglasses is reduced, the cosmesis of the eyeglass prescription is enhanced, and the patient is more compliant during the therapy process.
In the article recently published in Optometry and Vision Development, Drs. Press and Press present a case report that includes the use of Visual Evoked Potentials (VEPs) to measure the brain’s response to visual stimuli under different conditions. They were able to compare the VEPs with and without glasses, with different prescriptions, and before and after completion of an optometric vision therapy program. As the visual skills of this 4 year old girl improved and her reliance on the glasses was reduced, her brain’s responses to visual stimuli was significantly enhanced. The average increase in the amplitude of the VEPs increased by 103% post-vision therapy!! The VEPs also demonstrated that when presented with smaller, more detailed visual targets, her brain’s response was increased when she wore a minor prescription. Therefore, at the end of vision therapy, it was decided that it would be in her best interest to wear the glasses when engaged in extended reading and other near activities, but not during outdoor play or watching TV.
Kudos to Drs. Press and Press for using science to demonstrate what we know to be true in clincal practice. Not only were they able to measure changes in brain activity with optometric vision therapy, but they were also able to determine the best prescription for this young child. The reverse engineering of the hyperopic anisometropic amblyopia was a documented success!
Read more about amblyopia here.