The ability to perceive the world in three dimensions and to see clearly at near and far ranges is coordinated by key eye motor functions, including a mechanism called convergence and accommodation that allows us to see objects at different spatial depths by controlling two sets of muscles to reduce double and blurry vision.
For a small but significant fraction of the population, however, the left and right eyes do not work as a team. The result, known as convergence insufficiency (CI), leads to visual stress and strain and headaches. The impacts on cognition and learning can be severe, particularly for children.
"Near reading is particularly uncomfortable for people with CI, who experience visual stress and fatigue after 15 to 20 minutes of reading," notes Tara Alvarez, a professor of biomedical engineering and the director of NJIT's Vision and Neural Engineering Laboratory. "This is really a problem for students. In terms of cognitive load, if someone is expending significantly more energy acquiring visual information, then less energy is available for cognitive function. This puts students with CI at a competitive disadvantage compared to their peers, especially for timed tests."
Alvarez and other experts in the field estimate that between 12 and 24 million people in the United States, or 4 to 8 percent of the population, have this vision dysfunction. Among people with traumatic brain injuries, the percentage may be as high as 40 percent; children with Attention Deficit Hyperactivity Disorder (ADHD) are three times as likely to experience it. And while the problem was identified more than a half-century ago, "we still don't know why CI happens. We don't know why one person develops it and another doesn't," Alvarez says.
Armed with a five-year research grant from the National Institutes of Health, Alvarez is poised to begin untangling some of the mysteries behind CI. In a study that is the first of its kind in terms of size
|Contact: Tanya Klein|
New Jersey Institute of Technology