McGill University

For the roughly three percent of the population that suffers from amblyopia, or "lazy eye," the best current treatment option -- covering the stronger eye to force the weaker one into better behavior -- works only some of the time in kids and has been totally ineffective in adults.

Now researchers out of McGill University in Montreal say that playing Tetris may ultimately treat the disorder in adults because the puzzle video game trains the eyes to work together as information is distributed across them in a complementary fashion.

"The key to improving vision for adults, who currently have no other treatment options, was to set up conditions that would enable the two eyes to cooperate for the first time in a given task," Dr. Robert Hess, senior author of the paper published this week in the journal Current Biology, said in a school news release.

Amblyopia is caused by poor processing in the brain that leads to the dominant eye suppressing functioning of the weaker one. By connecting differently shaped blocks as they fall in Tetris, the eyes are forced -- perhaps even enjoyably so -- into cooperation, alleviating suppression of the weaker eye and retraining the brain to use both equally.

Researchers tested 18 adults with amblyopia, nine of whom played Tetris with the stronger eye patched and nine of whom played it dichoptically, using head-mounted video goggles that allowed one eye to see only the falling objects and the other to see only the ground objects. Two weeks later the group using both eyes showed dramatic improvement in the vision of the weaker eye and even in perception of 3D images, while the group with the patch showed only moderate improvement. Then, when the patch was removed, that group ultimately caught up with their goggle-playing forebears.

The team plans to test this approach in children later this year in a clinical trial that spans North America.