According to a popular adage, the eyes are the window to the soul. But the eyes may also help diagnose mental disorders such as schizophrenia, depression and autism, according to researchers at the University of Illinois at Chicago.

Researchers have long reported irregularities in the eye movements of patients with mental disorders. Patients with autism have difficulty maintaining eye contact with others. Schizophrenics are often unable to keep their eyes focused on slow-moving objects. These abnormalities, researchers say, reflect defects in the neural circuitry of the brain—defects that are well documented but as yet poorly understood.

Funded by the National Institute of Mental Health, John Sweeney, director of the Center for Cognitive Medicine in UIC's department of psychiatry, and his colleagues are spearheading a research initiative to study and catalog eye movement patterns in patients with psychiatric disorders.

In these experiments, test subjects with maladies ranging from severe brain trauma to bipolar disorder undergo a battery of visual tests. They wear infrared glasses linked to a computer that measures and records subtle eye movements. Similar tests, administered to the participants in an MRI scanner, allow the researchers to monitor brain function associated with eye movement and pinpoint inconsistencies. Sweeney says noting parallels in abnormal eye movement and brain activity "gives us an objective way of evaluating patients and treatment response that clinical evaluations, while crucial, can't provide." This line of research may also help identify at-risk individuals before the onset of mental illness.