MONDAY, Feb. 2, 2004 (HealthDayNews) -- Inner retinal and optic nerve disease may be a major risk factor for sleep disorders, says a study in the February issue of Ophthalmology.
The study included 25 visually impaired people, aged 12 to 20, and 12 people with normal sight. Researchers compared the sleep-wake cycles of both groups over 14 days.
Previous research has suggested the retina contains non-visual photoreceptors in the inner ganglion cell layer that communicate directly with areas of the brain involved in circadian rhythms. In light of that, the visually impaired people in this study were divided into two groups -- those with optic nerve disease and those without.
"The study showed the subjects with optic nerve disease were 20 times more likely to have pathologic levels of daytime sleepiness, as indicated by napping, than the subjects with normal sight," researcher Dr. Russell N. Van Gelder, an assistant professor in the department of ophthalmology and visual sciences at Washington University Medical School, says in a prepared statement.
"They were also nine times more likely to have pathologic sleepiness than the visually impaired subjects who were blind from the non-optic nerve diseases. We suspect these patients have difficulty using daylight to synchronize their internal rhythms to the outside world," Van Gelder says.
The study also found the people with the optic nerve disease also had highly variable wake-up times and had greater difficulty falling asleep than the others in the study.
"Taken together, these results lead to the unexpected conclusions that eye disease is a risk factor for sleep disorders and whether the optic nerve is healthy or diseased strongly influences the risk of sleep disorders," Van Gelder says.
Doctors need to be aware of this when treating people with optic nerve diseases, he suggests.
More information
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