Researchers in England say visual stress may be a sign a person is suffering from Chronic Fatigue Syndrome (CFS), the difficult-to-diagnose condition that can leave someone perpetually exhausted.
People suffering from CFS are more likely to experience what is known as pattern-related visual stress, resulting in exhaustion and discomfort when faced with repetitive patterns with stripes, for instance when reading lines of text, scientists at the University of Leicester report.
As a possible indicator, such stress may help doctors diagnose CFS, which can be difficult to pin down as a diagnosis because its symptoms are also found in many other illnesses, researchers say.
CFS, also known as Myalgic Encephalomyelitis (ME,) is a disabling condition that can significantly affect a person's everyday life and does not get better even with sleep or rest.
"Diagnosis of ME/CFS is controversial," says study leader Claire Hutchinson from the university's Department of Neuroscience, Psychology and Behavior. "With the exception of disabling fatigue, there are few definitive clinical features of the condition and its core symptoms overlap with those often prevalent in other conditions."
Because of that, a diagnosis of CFS is quite often suggested as a last resort, sometimes after the patient has been subjected to inappropriate and ineffective treatments of a misdiagnosed disorder, she notes.
"It is imperative therefore that research focuses on identifying significant clinical features of CFS/ME with a view to elucidating its underlying pathology and delineating it from other illnesses," she says.
Any visual abnormalities such as those seen in the study could serve as verifiable, measurable behavioral markers of the condition, the researchers suggest.
For the study, 20 patients diagnosed as having CFS and 20 people without it viewed increasingly repetitive visual patterns and then recorded how many distortions they had experienced as they viewed each of the patterns.
Patients suffering with CFS were more likely to report such distortions, the researchers reported in the journal Perception.
The work is one of the first to focus on visual problems associated with Chronic Fatigue Syndrome, notes Neil Abbot, director of research and operations at ME Research UK, which funded the study.
"Around three-quarters of people with ME/CFS report a range of eye and vision-related symptoms that interfere with their everyday lives, yet there has been very little scientific investigation of the problem," he points out.
The research strongly points to the possibility of vision anomalies, including pattern-related visual stresses, serving as a diagnostic tool in looking for CFS, he says.
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