Vision recovery possible via residual vision
There is a good news for patients who have lost part of their vision due to glaucoma, optic nerve damage or stroke.
Scientists have now discovered that success of vision restoration training (VRT) depends mostly on activity of residual vision that is still left after the injury.
"Our findings confirm the special role of residual structures in vision restoration, which is mediated by surviving cells in partially damaged brain tissue," said Bernhard A. Sabel of the Institute of Medical Psychology, Otto-von-Guericke-University of Magdeburg, in Germany.
Both local neuronal activity and activity in the immediate surrounding influence the development of visual recovery "hot spots".
"Hot spots" were defined by the researchers as those locations that were initially impaired at baseline but then recovered after VRT training, while "cold spots" remained impaired where vision training did not help.
"This shows that recovery of vision is mediated by partially surviving neurons," said the study published in the journal Restorative Neurology and Neuroscience.
Researchers conducted a retrospective analysis of multiple visual field tests before and after at least six months of VRT in 32 stroke patients with hemianopia - loss of vision in half of the visual field.
The test, known as high-resolution perimetry (HRP), presented visual stimuli on a computer monitor to which the patient had to respond by pressing a key on the keyboard.
Repetitive stimulation through daily one-hour vision training with VRT was directed at
the "areas of residual function" to strengthen their performance.
The massive visual stimulation presented during VRT enhances visual recovery by forcing subjects to focus their attention on "compromised" sectors of the visual field which are partially damaged and repeating this daily helps recover vision loss, suggested
"This new understanding now allows us to offer vision training on the Internet through online training," he said.
(Posted on 03-01-2014)