Take a trip back in time with me, to your Biology 101 undergraduate course, freshman year, first semester. I know for some of us freshman year is a bit hazy, but I am assuming you attended MOST of your classes. Try and recall that first introduction to the brain, where your professor said “The brain can not regenerate; our neurons are genetically pre-determined and we make no new connections after the brain has stopped growing.” I’m sure you believed it to be a valid and true statement; after all, it was in every textbook you were cramming from. Well let me tell you a different and more recent version of the story; the neurons in your brain in fact DO make new connections, and Optometry is at the forefront of that discovery. OD’s everywhere are proving the existence of “neuroplasticity” in their practices daily, where patients who once thought themselves incapable of binocular and clear vision are discovering quite the opposite.
Neuroplasticity is understood as the capability of neurons and neural networks in the brain to change their connections and behavior in response to new information, sensory stimulation, development, damage, or dysfunction. Although neural networks carry out specific functions, they retain the capacity to deviate from their usual functions and to reorganize themselves. This property is the basis for optometric vision therapy and visual rehabilitation following traumatic brain injury. While certain facets of our brain are genetically programmed, changes can occur as a result of experience. These experience-dependent changes can transpire throughout infancy, childhood, adolescence, and adulthood. Neuroplasticity is the basis of neurorehabilitation, and this includes speech and language therapy, motor control, cognitive functions, and vision rehabilitation. Scientists believed that once a human had passed their “critical period” rehabilitation exercises for vision and other neurologically controlled systems were mostly ineffective. The “critical period” is a limited time in which a biological event must occur in order for a cortical brain change to be fully functional, which is approximately until age 12 for humans.
Simply put, brain function can be modified and molded by the environment with which it interacts. How is this possible and how is Optometry proving it? Our discipline has been working with these concepts for years, mainly in the treatment of amblyopia and strabismus. Techniques such as patching the “seeing” eye, forces the brain to interpret stimuli that is being received by the amblyopic eye. New cortical connections within the brain form, and the previously under or un-developed cells designated for visual perception are stimulated, leading to better vision and resolution of detail. Although ODs have been offering special therapies for children with vision disorders such as amblyopia with great success, the question remained as to whether or not these same therapies would be just as effective in adults. After all, the critical period had passed, and biology was in favor of a limited time only type of treatment protocol.
Recent research indicates that indeed adult brains exhibit neuroplasticity, and adult neural stem cells are now known to generate new neurons throughout our lives. Success stories of vision therapy are abundant in the current literature, with patients regaining use of their amblyopic eye and acquiring stereopsis for the first time in middle age. Although prognosis may be guarded, vision therapy treatments are no longer taboo in the adult population. Approximately 70% of all sensory input fibers to the brain are related to vision and visual processing, so ODs play a critical role in the rehabilitation of visually related problems. Regardless of age, patient attention, awareness, and task repetition during vision therapy techniques have proven to be beneficial. With this new information, ODs have found a new niche and gained more rewarding experiences with their patients. For more information about neuroplasticity, vision therapy, and vision rehabilitation for traumatic brain injury, please consult the following organizations:
COVD (College of Optometrists on Vision Development)
OEPF (The Optometric Extension Program Foundation)
NORA (The Neuro-Optometric Rehabilitation Association)
Article By: Stefania Paniccia; IAUPR 2013 optometry student
(featured image courtesy of aaronbrimhall)
