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Total Blindness and Non-24 Sleep Disorder

The circadian clockRecently, you may have been hearing and seeing commercials for a blindness-related sleep disorder called Non-24. In the radio ads I’ve heard, the narrator says he’s totally blind and suffers from the condition. The media spots are sponsored by Vanda Pharmaceuticals, which recently received approval from the U.S. Food and Drug Administration for a drug called Hetlioz to treat Non-24.

The ads have piqued our curiosity at the Foundation Fighting Blindness. We’ve been wondering what Non-24 is, and who it affects. As an organization that funds research for retinal degenerative diseases — e.g., retinitis pigmentosa, Leber congenital amaurosis, Stargardt disease, age-related macular degeneration and choroideremia — we were especially interested to know if Non-24 affects people with these conditions.

So I spoke with sleep-disorder experts Steven W. Lockley, Ph.D., at Harvard, and Helene Emsellem, M.D., medical director at The Center for Sleep Disorders in Chevy Chase, Maryland. What they told me is that Non-24 is not likely to affect most people with retinal degenerative diseases. Here’s more information on what I learned.

What is Non-24?
Our bodies (and brains) operate on a circadian clock, which regulates many biological systems, including sleeping and waking. For most people, the clock is approximately 24 hours and reset everyday by the first perception of light.

Dr. Emsellem says that Non-24 is a very rare condition affecting many (but not all) people who are totally blind and have absolutely no light perception. Their circadian clocks become out of sync as a result. Furthermore, their sleep-wake cycles often drift day to day by varying degrees. For example, if their cycle is drifting by 30 minutes, they may feel like going to sleep at midnight one day, 12:30 a.m. the next, and so on.

People with Non-24 have trouble going to sleep at night and staying awake during the day. The condition can wreak havoc on their lives, especially those in school, working or caring for a family. As if being totally blind in the sighted world wasn’t difficult enough!

Why Most People with Retinal Degenerations are not at Risk
While many people with retinal degenerative diseases have severe vision loss and use accommodations such as navigational canes, guide dogs, talking computers and other high-tech gadgets, a vast majority maintain some level of light perception and are, therefore, not at risk for Non-24.

Even people who have lost all of their rods and cones to a retinal degenerative disease may not get Non-24. That’s because the cells in the retina that regulate the circadian clock — photosensitive ganglion cells — usually survive after photoreceptors are gone. Even though a person with a retinal degeneration does not experience light perception, there is a good chance his or her photosensitive ganglion cells are still functioning and sending signals back to the brain to synchronize the person’s circadian clock.

Who is at Risk of Non-24?
Researchers have found that people more likely to have Non-24 are those who have advanced conditions or diseases which affect retinal ganglion cells, and/or the optic nerve, which is the cable that sends signals from the retina back to the brain. As reported in the journal Sleep, these individuals can include people with: traumatic optic neuropathy, advanced retinopathy of prematurity, severe retinal detachment and retinoblastoma, a cancer of the retina which is sometimes treated by removal of the eyes.

Dr. Emsellem says that people with normal vision can have Non-24, but those cases are extremely rare, and scientists aren’t sure why these individuals are affected.

Managing Sleep Disorders
Just because a blind or visually impaired person doesn’t have Non-24 doesn’t mean he or she doesn’t have another sleep disorder that is or isn’t related to vision loss. Lifestyle habits, such as diet, exercise and stress management, can all be affected by vision loss, and they significantly impact the quality and duration of sleep.

Dr. Emsellem reports that more than 50 million people in the United States have sleep disorders or are not satisfied with their alertness during the day. She provides helpful information on sleep disorders and getting a good night’s rest on her website. She strongly encourages people to seek help from a sleep specialist for treatment of persistent sleep-alertness issues.


7 Responses to 'Total Blindness and Non-24 Sleep Disorder'

  1. Rachel says:

    Very interesting read, I saw this commercial recently and was wondering about the condition. Thanks for the post!

  2. One of the most common and serious problems addressed by the Sleep Disorders Center is sleep apnea. “Recent studies have shown that a person with untreated severe sleep apnea for a decade or more may have greater than four times the risk of diseases like heart attack and stroke as someone who doesn’t,”

  3. My father is blind.he is75years old is it safe for him to use this medicine

  4. Firoz says:

    My daughter was born at 24 weeks. She had severe detachment in one eye and total detachment in another. Although few surgeries have been done but the vision seems to be leas. she is 3.5 year old and has yet not learned to speak completely, her vision is yet not completely predictable. Compared to her age she sleeps very late and has troubles to wake up for school.
    I am an Indian national presently in Congo.
    Please advise if there are any new development to improve the retinal detachment conditions and the sleep.

  5. I am 57 yrs old I would like to get more info
    On further research. My doctors in Palo Alto , CA
    Have told me I have retina diseases. Can you help
    Me with this issue please!!!

    • EyeOnTheCure says:

      You should know that there are three inherited forms of RP: recessive, dominant and X-linked. If you are not sure which type you have, you should ask your ophthalmologist. For information on inheritance types, please see the following web link to download a PDF document on inheritance:
      http://www.blindness.org/sites/default/files/inheritance_of_retinal_degeneration_-_july_2012.compressed.pdf
      You should consider genetic testing to try and identify the mutant gene responsible for causing the disease. If the gene is identified, medical databases such as PubMed (http://www.ncbi.nlm.nih.gov/pubmed/) can be searched to identify any research that is being conducted. With a molecular diagnosis, one may also qualify for gene therapy trials that are taking place. For information on genetic testing, please see the following web link to download a PDF document:
      http://www.blindness.org/sites/default/files/genetic_testing_booklet_201311rev.pdf
      Whether the disease gene is identified or not, one should still consider participating in FFB’s “My Retina Tracker”, a free registry that monitors clinical trials that are recruiting for various retinal diseases. For more information on “My Retina Tracker” please see the following web link:
      https://www.myretinatracker.org/
      It may also be helpful to periodically check the website: http://WWW.CLINICALTRIALS.GOV which is maintained by the National Institutes of Health and contains a searchable list of clinical trials for most known diseases. Each clinical trial listing will provide you with information on what the study is about, the requirements for participating and contact information.

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