New research is challenging the long-held belief that stroke-induced blindness is untreatable and therefore permanent.
Though speech and motor impairments following stroke are routinely treated with great success, therapies for recovering vision have historically been thought impossible. Many stroke survivors have been consigned to permanent blindness as a result. Fortunately, a new study demonstrates that by stimulating healthy parts of the brain, vision recovery following a stroke is possible.
Krystel Huxlin, Ph.D., a neuroscientist and associate professor at the University of Rochester Eye Institute, helmed the study with seven stroke survivors of various ages who had all suffered severe damage to their primary visual cortex, an area of the brain responsible for making sense of visual stimuli so that a recognizable image can be perceived.
Primary visual cortex damage leaves stroke survivors with a vague awareness of visual stimuli but no way to make sense of what they are seeing or discern clear images. This leaves them unable to drive, navigate simple spaces, identify everyday objects, and live independently. The prospect of vision recovery holds profound promise for restoring hope to vision-impaired stroke survivors by helping them to regain their independence and quality of life.
The research team focused on motion perception since this is the aspect of vision most central to everyday tasks. The team was interested in whether healthy areas of the participants’ brains could take over the functions previously handled by the stroke-damaged primary visual cortex. They hypothesized that with enough stimulation, these areas of the brain might learn to clearly “see” what was currently perceived by the participants as an amorphous movement.
How did they test this? They showed participants interactive computer screens with twinkling visual stimuli (a cluster of dots) that were pre-programmed to appear and disappear at regular intervals within different areas of the participants’ field of blindness. Interestingly, even though the participants couldn’t describe what they were seeing, they were aware something was happening. Participants made their best guess about whether the dot cluster was moving to the left or the right. When they correctly identified the direction of movement, a chime would sound, teaching the brain to better “see” the dot cluster.
Even though the participants couldn’t perceive the dot clusters, their brains clearly registered and responded to them. Deliberate training and practice enabled the relationship to be restored between the brain and the conscious perceiver to result in vision.
These findings are in keeping with the research on neuroplasticity, a concept that refers to the brain’s ability to continually adapt in response to new challenges. By stimulating the brain through intensive daily training for 18 months, participants were able to substantially recover their vision. Two of the participants were once more able to drive, and several regained much of the independence they had enjoyed before their stroke.
The results of the study are a testament to the power of research in identifying and testing long-established assumptions in a way that opens up new possibilities for recovery and wellbeing. At OCLI, we pride ourselves on offering our patients the latest advancements in eye care research and treatment. Whether your eyewear prescription needs updating or you’re seeking cataract surgery or permanent vision correction, we have a customized solution for all of your eye care needs. Reach out to us today and see why we’re known as New Jersey’s friendliest and most comprehensive eye care providers.