VANCOUVER, Canada: Playing a video game that involves shooting enemies on a battlefield has helped some adults who were born with a rare eye disorder improve their vision later in life, scientists have said.

The research shows that some sensory abilities that may seem permanently impaired can be improved in adulthood, according to lead investigator Daphne Maurer of McMaster University in Canada.

Maurer and colleagues followed children born with a rare cataract disorder in both eyes that required surgery and corrective contacts. All were deprived of normal vision as infants between three and 10 months.

As these children grew to adults, their vision improved but never reached 20/20, and they showed some deficits in face perception, sharpness, direction of motion, peripheral and binocular vision.

Since previous research on people with certain eye disorders had shown improvements after playing a type of video game known as a first-person shooter, in which the player wields a gun and blows up foes, Maurer decided to try it on her subjects.

Six patients between the ages of 19 and 31 were tracked for a period of one month, in which they played the Electronic Arts video game “Medal of Honor” for a total of 40 hours – no more than two hours a day, five days a week.

Five of the six showed improvement in their vision, each moving closer to 20/20 from baseline ranges of 20/32 to 20/100, with improved ability to recognize faces, see small print and judge the direction of moving dots.

“About two-thirds of the things we measured improved simply from playing an action video game,” Maurer told reporters at the American Association for the Advancement of Science annual convention in Vancouver.

For the average person, that’s about the same as being able to read two lines smaller than they presently can on an eye chart, she added.

“I think it tells us that the visual nervous system is still plastic enough to either form or reveal connections in adulthood ... and we suspect that might be true for any kind of visual defect.”

Maurer, who said she is not a “gamer,” admitted some reticence to asking people to play a violent video game for her study.

“Certainly we don’t relish ask[ing] adult patients who are nongamers to play a first-person shooter for 40 hours,” she said.

“They know what they are getting into and they know there is a small risk they may become addicted to such games as a result of our intervention. That is why we limit them to 10 hours a week and no more than two hours a day,” she added.

However, the visual benefits of the game were so great that it made the effort worthwhile, she said.

The fast-paced game requires players to monitor what is right in front of them and what is in the periphery, increasing levels of dopamine and adrenaline that may make the brain more flexible to improvements in visual acuity.

“It is also called adrenaline for action, because you not only have to make a judgment based on what is going on on the screen but you have to act on it and you have to act on it from a real world perspective,” she said.

“So we think the manufacturers built into these games the effective ingredients for retraining the visual brain in adulthood.”

Now, Maurer and colleagues are working on creating their own video game for patients, gleaning the same characteristics of Medal of Honor but adding some elements to train people’s brains to improve binocular vision.

“We are currently as a network [with other scientists] building our own game which we hope will be even better because it won’t be violent,” Maurer said.