York University researchers have designed a computer game that corrects a common vision problem more effectively than conventional, boring therapies.
The game, a 3-D version of Pac-Man, helps patients with a condition called convergence insufficiency learn to align their eyes.
Right: Researchers developed a 3-D version of the popular game Pac-Man. Image of the traditional Pac-Man game courtesy Wikimedia Commons.
The disorder can cause headaches, blurred or double vision, eye strain and reading problems. It affects up to five per cent of the population and is typically treated with exercises requiring repeated convergence of the eyes.
“The problem is, they’re really boring, monotonous exercises,” says Robert Allison, professor of computer engineering at York University, who led the research. “Patients, particularly younger people, aren’t motivated to practise, so they don’t see results.”
Allison says office-based therapies are more effective than those performed at home, but are more 
costly and time-consuming. “We were looking for a way to make at-home therapy more efficient, and more effective,” he says.
Right: Robert Allison
Allison and colleagues conducted a study in which patients were instructed to play the game for 20 minutes a day, five days a week, over a period of two weeks. They found that as subjects advanced through the game, the coordination of their eyes improved; some felt less eye strain when looking at nearby objects.
Patients were equipped with a 3-D viewer called a stereoscope. With their eyes in the right position, they could see the 3-D images hidden in the game, and advance to the next level.
Left: Researchers took the basic Pac-Man concept and developed a stereoscopic version. Patients are equipped with a 3-D viewer and if their eyes are in the right position, they are able to see the 3-D images hidden in the game and advance to the next level. Photo courtesy Prof. Robert Allison.
The game is divided into a split-screen format; sets of mirrors in the stereoscope – one set per eye – are directed to opposite halves of the screen. Each eye sees two displays: a 3-D representation of the game and random-dot images containing hidden stereoscopic geometry. Researchers can manipulate these mirrors to vary the distance between them, in order to control the angle at which the eyes converge. The hidden stereoscopic imagery is essential to advancement in the game and provides a check that players have their eyes in the correct position.
Results to date suggest the game will improve compliance on vision therapy exercises. “On average, we got the training times we were looking for,” says Allison. “While the study size is still small, all subjects so far have shown improvements and some reported that their symptoms have disappeared.”
The study was conducted in partnership with the University of Waterloo’s School of Optometry, where Allison is an adjunct professor. It appeared in the proceedings of the August 2008 international conference, Virtual Rehabilitation, and was co-authored by Tristan Carvelho (BASc Spec. Hons. ’05, MSc ’08), a former master’s student in York’s Department of Computer Science & Engineering.