Macular degeneration is the leading causes of blindness in industrialized countries. Now, University of Waterloo researchers have found that a single session of non-invasive brain stimulation of the visual cortex can reduce the effects of the disease, a discovery that could eventually allow patients with macular degeneration to recover their vision.
Patients with macular degeneration lose central vision and are forced to rely on peripheral vision. But due to mechanisms in the brain that combine images, they can have difficulty segregating an object from others that are in close proximity. This phenomenon is called crowding.
The research team, led by Ben Thompson of the School of Optometry & Vision Science and Rajkumar Raveendran from Envision Research Institute in Wichita, Kansas, found that a 20-minute session of transcranial direct current stimulation (tDCS) in people with normal vision reduced crowding. The researchers are hopeful that this finding could be the first step towards using tDCS as a treatment for patients with macular degeneration.
Such treatment could be an attractive alternative or addition to existing methods using perceptual learning, in which patients learn to decrease the effects of crowding by performing visual tasks repeatedly.
“Perceptual learning can reduce letter crowding for patients with macular degeneration. However, this typically requires intensive training, which may be a barrier for patients. Additionally, the learning does not always transfer to non-trained stimuli. That’s why this discovery is so promising; it addresses all of these concerns,” said Thompson.
“This result lays the foundation for future work investigating whether tDCS may be useful as a visual rehabilitation tool for individuals with central vision loss who rely on peripheral vision,” said Thompson.
This research was published in the peer-reviewed journal, PLOS ONE.