Video Games Help Improve Vision Training

Unlike eye patches on dominant eyes to make the lazy eye stronger, push-pull stimulates both eyes, with the weaker eye exposed to more complex images that create a stronger stimulus. In this way, both eyes are encouraged to interact as they should, but the dominant eye's power in the relationship is suppressed.

The games feature groups of lines with differing orientation, and players wear red-green three dimensional (3D) glasses that filter the images to each eye. The dominant eye is stimulated with only a full screen of horizontal lines. The weak eye sees bordered disks that contain vertical, horizontal, or diagonal lines imposed against a background of those same horizontal lines; the contrasting disks serve as the focal points of the games. In the cat and mouse game, a Pac-Man-shaped cat must eat scurrying mice (disks) that have lines oriented in the same way as the cat. In another game, users view a matrix of disks containing lines of different orientation and must use the cursor to line up a master disk with disks that have the same line orientation.

According to the researchers, the games target important pathways in the brain that must be active to produce balanced vision, unlike patching which results in the dominant eye remaining completely unused. In pilot testing, weak-eye vision improved to 20/20 and 20/50 in two adult research participants with lazy eyes whose vision was 20/25 and 20/63, respectively, before the training began. The study was presented at the annual meeting of the Society for Neuroscience, held during November 2014 in Washington DC (USA).

“We make sure the weak eye is seeing the contrasting images at all times. The strong eye has stimulation, but it is cortically suppressed; that is pull. The weak eye is pushed to work,” said lead author and study presenter Prof. Teng Leng Ooi, PhD. “And even if an eye is not stable, wherever your eyes are sharing vision, the corresponding retinal points are being stimulated. We think that makes our game design highly effective.”

“The training we initially designed was quite boring. Participants had to keep their eyes still all the time and keep looking steadily at the same target, and it lasted for 1½ hours,” added Dr. Ooi. “With the games, participants are working on a laptop and each game lasts only a few minutes. Therefore, even if the total training duration is long with repetitive game playing, the participants only need to concentrate hard for a few minutes at a time while they enjoy the challenge of the game.”

Amblyopia is a childhood disorder that affects an estimated 2%–3% of the population. It results when the neural pathway from one eye to the brain does not develop because the eye is sending blurry and/or incompatible images, usually due to strabismus (cross-eye). The lack of balance in the eyes typically leads to poor depth perception, and the greater the imbalance, the more depth perception is impaired.

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