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Aging Eyes Blamed For Seniors' Health Woes
Hugh Pickens writes "Scientists have looked for explanations as to why certain conditions occur with age, among them memory loss, slower reaction time, insomnia and even depression looking at such suspects as high cholesterol, obesity, heart disease and an inactive lifestyle. Now Laurie Tarkan writes that as eyes age, less and less sunlight gets through the lens to reach key cells in the retina that regulate the body's circadian rhythm, its internal clock that rallies the body to tackle the day's demands in the morning and slows it down at night, allowing the body to rest and repair. 'Evolution has built this beautiful timekeeping mechanism, but the clock is not absolutely perfect and needs to be nudged every day,' says Dr. David Berson, whose lab at Brown University studies how the eye communicates with the brain. Dr. Patricia Turner, an ophthalmologist who with her husband, Dr. Martin Mainster has written extensively about the effects of the aging eye on health, estimate that by age 45, the photoreceptors of the average adult receive just 50 percent of the light needed to fully stimulate the circadian system, by age 55, it dips to 37 percent, and by age 75, to a mere 17 percent and recommend that people should make an effort to expose themselves to bright sunlight or bright indoor lighting when they cannot get outdoors and have installed skylights and extra fluorescent lights in their own offices to help offset the aging of their own eyes. 'In modern society, most of the time we live in a controlled environment under artificial lights, which are 1,000 to 10,000 times dimmer than sunlight and the wrong part of the spectrum,' says Turner. 'We believe the effect is huge and that it's just beginning to be recognized as a problem.'"
I usually keep the lights here in the basement off.
I believe the article mentions that cataract surgery will fix this problem, allowing the full amount of light (in the correct part of the spectrum) back in. (In fact, as a recent slashdot story mentioned, it sometimes allows you to see in the UV!).
I wonder if people will choose to have cataract surgery done even if they have no cataracts. My mom was recently evaluated for the surgery, evidently it's a (relatively) simple procedure; the patient goes home the same day and only has mild discomfort for a few days.
Hi Carl!
It wouldn't be a bad idea, but honestly if you had a problem you'd know it by now, take it from someone with a circadian rhythm disorder. During my bad spells I have every symptom of an 80 year old man; lack of concentration, poor memory, poor reaction time, moodiness and anger, physical exhaustion, and of course extreme drowsiness. And that's even if I manage to get a decent 6 hours of sleep, when your body is determined that it is time to sleep it does not appreciate being kept awake. You can push through it for a day or two, maybe a week with enough willpower, but 3 weeks into a stretch where your body thinks that 5AM to 1PM is the perfect time to sleep when family, work, and friends all think differently... well... yeah... you'd know if you had circadian rhythm problems.
I actually have a circadian rhythm disorder myself. Between 2005 and 2010 my sleep 'schedule' would go around the clock fully over a period of every 1-2 weeks. So, part of the time I was up during only the night, sometimes in between, sometimes during normal parts of the day. I have a greater than 24-hour sleep cycle naturally it would seem. However, I've been maintaining a pretty normal schedule for 1.5 years now. I started using sublingual 2.5mg melatonin lozenges after my sister told me about them. It totally did the trick in my case.
Of course, more relevant to the article, there are lamps you can also buy for bright light therapy. I actually just got myself one about 11 days ago. It can take up to a few weeks to have an effect, and I think I've finally started to feel a measurable effect over the past 3 days, but I'll see how it goes before I make a final determination. According to what I've read, it can help with circadian rhythm disorders, but I personally bought it for the antidepressant effect. Perhaps I'll be able to switch over to using only the light, which would be pretty neat. But I wouldn't complain if I still had to use melatonin.
I had cataract surgery in my left eye (which is the dominant eye) four years ago, at age 49. I had cataract surgery in the right eye 18 months later.
Simply put--as your eyes cloud over, your brain has to work substantially harder to compensate. Your brain has to decipher blurred vision, compensate for the "halo" effect cataracts give you around bright lights (the reason why older people don't drive at night is the halo effect of oncoming headlights--completely blinding them).
All of that changes with cataract surgery--you don't just see better. (And you see MUCH better--if you wore corrective lenses beforehand they implant a custom-fit lens that corrects your vision to 20/20 or better.) All of the "clock cycles" that your brain was devoting to countering the effects of cataracts (even things like keeping your balance) are all of a sudden freed up. The change is dramatic--it really is life-transforming.
My mother-in-law is 90--she had cataract surgery last fall. Last summer, before the surgery, her daughters were wondering about "what are we going to do about Mom"--at the time I suggested that they wait till after the cataract surgery; I was sure it would have a big impact. Boy, did it--my mother-in-law is active, alert, far more capable, and busy with plans for an expanded vegetable garden this summer.
Until you go through the experience, you can't really understand how much effort your brain puts into interpreting what you see. The impact of cataract surgery is unbelievable.
Is there any psychological correlation with this phenomena and the desire to move to the brighter sunnier states - like Arizona and Florida - when one hits 75?
I have some good news for you: everyone is blind in the middle of their field of vision in a dark environment. The centre of the retina is extremely crowded with bright-light/colour vision cones, which is what gives us our excellent ability to see detail. There's just no room for rods left over, so we get a dark spot in our night vision instead.
Bio questions? Ask me to start a Q&A journal. Computer analogies available for most topics!
What are the effects of too much exposure to light?
Combustion.
Cataracts are one possible effect; clouding of the lens due to exposure to bands of UV light. Certain medication can also contribute to the effects of light on the eye, but the common one that many people use without knowing the potential effect is St. John's Wort.
I'm profoundly affected by the shortened (and usually sunless) days beginning in the fall, through the awful winter, and into the spring. (I'm self-diagnosing, but I'd say it qualifies as SAD.) I've used St. John's Wort in the winter months with a reasonable degree of success, but I think adding bright light to my work area helped a lot more. As in, four 300W fluorescent bulbs.
Much to my chagrin, however, I learned that St. John's Wort and Bright Light don't Mix.
Cataracts are (generally) easily treated, thankfully, but that might not be the extent of the possible effect. And I don't particularly want cataracts before I hit 40.
A preposition is a terrible thing to end a sentence with.
Everybody in this thread - The natural 25-26 hour schedule is completely normal for most diurnal mammals. They've done research with humans giving them NO time queues for days, and it turns out EVERYBODY falls into a slightly over 24-hour schedule.
The conclusion here is that our chemical engines are too imprecise for us to evolve a dead-on circadian cycle. So instead evolution gave us an unaided circadian cycle that's calibrated with a mean of about 25 hours, so that people with a naturally extremely short cycle are still just over 24 hours, and it goes up from there. Then we get a natural reset cue to adjust the cycle every day to keep it in sync with the world. The primary component of the reset signal is sunlight exposure in the morning. If you get up at a reasonable time (near or after sunrise) and GET OUTDOORS for about 15 minutes, then you will feel like going to bed at the right time to get enough sleep and want to get up at about the same time the next day. We and our ancestors spent tens of millions of years with no choice but to receive natural light in the morning, so it was a pretty good system before we evolved to live in our parent's basements and stare at little screens all day.
I suffer big time from this - every day I want to stay up and get up about an hour or so later than I did the day before - but not if I'm spending much time outdoors, especially in the morning. When I'm backpacking, wholly cow do I just want to go to bed when it gets dark, and get up just after sunrise. If we spent the day exercising outdoors like evolution intended, we wouldn't have this problem... but good luck being able to/wanting to do that all the time. But if you just drag yourself out of bed and take a 15 minute walk outdoors, even if it's cloudy or right around sunrise, problem solved. It does get tricky if you have to be at work before sunrise. Or if you work night shift (which I did for about 2 years) you're just *'ed.
I think the light exposure causes melanin production on about a 14 hour delay, making us want top go to sleep about 16 hours after exposure. This is why melanin supplements near bedtime are somewhat functional as a surrogate for actual light exposure in the morning.
Or as an alternate solution, since the day gets longer by about 1.7 milliseconds per century, by my calculations you could just wait about 200 million years for the earth to get in sync with your natural clock.
Can anyone tell me how to set my sig on Slashdot?