Refocusing Vision | Cortical Reorganization
Refocusing Vision
Patient who develop age-related macular degeneration lose their central vision but their peripheral vision often is not damaged The UK Macular Disease Society has developed a method to train people to use the undamaged parts of their eyes to read and identify faces.
Patients can be taught to use their peripheral vision to make up for damage to their central vision, using “eccentric viewing” and “steady eye techniques” which means that by not looking directly at an object, but above, below, or to one side, they can see it more clearly.
The training process teaches patients where to focus their gaze to improve their vision. The method works, not only for general vision but for reading as well – by moving the text rather than the eyes so that the words move into the portion of the gazed where the patient has good vision.
Learn more about macular degeneration
SOURCE: BBC News Channel, April 10, 2009, https://news.bbc.co.uk/1/hi/health/7958838.stm
Cortical Reorganization
Not only can people be taught techniques for adapting to loss of central vision, but apparently the brain also begins to adapt.
A new study shows that when people with retinal disease such as macular degeneration use a peripheral part of their retina to compensate for their loss of central vision, their brain appears to compensate by reorganizing its neural connections – a cortical reorganization.
Researchers used functional magnetic resonance imaging (fMRI) to measure brain activity of patients performing tests that stimulate the peripheral areas of vision. They found that when patients did so brain activity was more active in the parts of the brain where activity is seen when central vision is employed.
The researchers feel that large-scale cortical reorganization of visual processing occurs in humans in who experience retinal disease. While several other studies have suggested that the brain can reorganize itself, this is the first study to show that this reorganization in patients with retinal disease is related to patient behavior.
Researchers are currently analyzing how long this reorganization takes and whether it can be assisted with low-vision training.
Researchers: Georgia Institute of Technology
Published: Reorganization of visual processing is related to eccentric viewing in patients with macular degeneration, Schumacher, et al, Restorative Neurology and Neuroscience, Volume 26, Number 4-5, 2008, 391 – 402.
