A brain-training video game that improved the vision of college baseball players by as much as two lines on an eye chart has been developed by U.S. researchers.

"This is something which I think could help almost anybody," said Aaron Seitz, a neuroscientist at the University of California, Riverside, who led the research.

Players on the university's baseball team improved their visual acuity by 31 per cent after training with the app. And that translated into better performance on the baseball field, where better vision improves the odds of hitting a ball travelling well over 100 km/h.

"What we found is they had fewer strikeouts, they were able to create more runs," Seitz told CBC's Quirks & Quarks in an interview that aired Saturday.

The players had more runs than predicted even after taking into account the natural improvement that would be expected over the course of the season. Further calculations suggest the improved performance helped the team to win four or five additional games.

But Seitz thinks the app has even more potential to help people with eye conditions such as lazy eye, glaucoma, or age-related macular degeneration. There are 100 million people around the world who have such low vision that glasses don't help, he added.

"All that they have to gain is the brain training element.… For these people, there's just really big real-world benefits that could be achieved if we're able to improve their vision."

Seitz and his colleagues developed their training program by poring through hundreds of studies, looking for different ways to enhance the brain's visual learning.

"What I decided to do with this app is to take everything I know and try to stick it together into a program that was designed to create the biggest learning effect," he said.

The program is a video game in which players are presented with targets in the form of fuzzy, striped blobs that are speckled across the screen.

"You're supposed to click on all these blobs. And then as you do this, they become harder and harder to see," Seitz said. The blobs become smaller and dimmer, and objects similar to the targets will start appearing as distractions.

"The program adapts to the limits of your vision."

The baseball players in the study trained with the program for 25 minutes at a time. Each of them did 30 sessions of training over two months.

At first, Seitz wasn't sure it would be effective, as the players already had better than 20/20 vision. But by the end of the training, their vision was even better, even in low light conditions.

"Some of the players after training were able to get down to 20/7.5," Seitz said. "What a normal person could read at 7½ feet, they could stand 20 feet back and read just fine."

Following the training, the team's year-over-year improvements were at least three times greater than the rest of the league in batting average, slugging percentage, on-base percentage, walks and strikeouts, the researchers determined.

Seitz is now working with more baseball teams and women's softball teams as well as non-athletes to try to understand what is causing the vision improvements. They are also hoping to confirm the results by comparing a trained group with a control group in a double-blind study — something they weren't able to do with the baseball players.