It’s long been thought that after childhood, it’s too late to treat “lazy eye” leading to permanent vision loss (amblyopia). But new research suggests that the visual cortex of the brain has enough “neural plasticity” to respond to treatment for amblyopia even in adulthood, according to the article by Dennis Michael Levi, OD, PhD, of UC Berkeley.
Suppose someone told you that researchers had discovered that a major cause of vision loss is treatable, and that the most promising new treatment is—playing video games? It may sound far-fetched, but those are the conclusions of a special article, “Removing the Brakes on Plasticity in the Amblyopic Brain,” in Optometry and Vision Science, official journal of the American Academy of Optometry.
What’s more, initial studies suggest that specially designed video games may be effective in improving vision for adults or older children with amblyopia. For his work on neural plasticity in amblyopia, Dr Levi was named winner of the 2011 Charles F. Prentice Award.
How Do New Findings on “Neural Plasticity” in Adults…
Amblyopia (“lazy eye”) is vision loss that occurs when one eye is weaker than the other—most often from strabismus, or “turned eye.” Over time, the visual cortex ignores the information from the weaker eye. The main treatment is patching of the better eye, which makes the weaker eye work harder.
For almost a century, vision scientists and clinicians have thought that amblyopia can only be treated in young children, while the brain is still developing—up to about age nine. As a result, conventional treatments like patching have rarely been used in older children and adults.
“However, new clinical and experimental studies in both animals and humans provide evidence for neural plasticity beyond the critical period,” according to Dr Levi. The research suggests that that the older brain is more adaptable, or “plastic,” than previously thought. Although plasticity is lower after early childhood, there are ways of enhancing it.
One potentially useful approach is “perceptual learning”—basically, improving various aspects of sensory function through repeated practice. Dr Levi explains, “Practicing visual tasks can lead to dramatic and long-lasting improvements in performing them, ie, practice makes perfect!” Researchers have developed perceptual learning approaches in which patients perform challenging visual tasks using only their amblyopic (weaker) eye).
…Lead to Video Games as a Treatment Amblyopia?
However, these perceptual learning tasks have some important drawbacks—they produce improvement only in specifically targeted visual tasks. Another problem is “the rather dull nature of the training”—the visual tasks are boring and monotonous, which makes people not want to spend much time doing them!
In collaboration with Daphne Bavelier, PhD, of the University of Rochester and Jessica Bayliss, PhD, of Rochester Institute of Technology, Dr Levi has been working on a new approach using video games for visual training. The goal is develop a new type of action game that will combine the fun and excitement of video games while targeting the visual skills needed to improve visual performance in the weaker eye.
Initial clinical studies suggest that video games may improve several aspects of visual performance. In one recent study, this approach to perceptual learning led to recovery of three-dimensional stereo vision in adults with established amblyopia—even after decades without normal binocular vision.
“These findings, [including] the results of new clinical trials, suggest that it might be time to reconsider our notions about neural plasticity in amblyopia,” Dr. Levi concludes. He emphasises that “careful controlled randomised clinical trials” will be needed to confirm the effectiveness of the new approaches.
“Our author’s studies of perceptual learning, and particularly using active video game play, provide evidence for neural plasticity and accompanying treatment success in adults with amblyopia,” comments Anthony Adams, OD, PhD, Editor-in-Chief of Optometry and Vision Science.