Recent research shows that people who have optic nerve damage are at increased risk for sleep disorder.
The study involved 25 people with visual impairment. The participants had their sleep-wakefulness cycles followed for 14 days, and their results were compared with those of 12 young subjects with normal sight. Researchers discovered those with optic nerve disease were 20-times more likely to have daytime sleepiness than those with normal sight. Additionally, the people with optic nerve damage were nine-times more likely to suffer sleepiness than even those were blind due to non-optic nerve disease.
Recent work has indicated that the retina contains non-visual photoreceptors that communicate with the area of the brain involved in circadian rhythms. Researchers say, "Physicians and other health care professionals should be sensitive to the possibility of daytime sleepiness or insomnia, particularly in patients with severe optic nerve disease."
Researchers add that these findings also suggest the need to try to maintain any remaining vision in people with optic nerve damage as it plays a crucial role in health and longevity.