Aging Eyes and Sleepless Nights

Here’s some health news that you can file into the “ugh!” category: There’s yet one more condition that’s trying to get between us and a good night’s sleep — and it’s one that’s nearly impossible to control. The lenses of your eyes are likely to naturally (and gradually) turn an icky yellow color as you age — and now a new Danish study, which was published in the September 1, 2011 issue of Sleep, suggests that the more severe the yellowing of the lens is, the more likely you are to have trouble getting a solid seven to eight hours of ZZZ’s a night.

I called Michael J. Decker, PhD, RN, the Byrdine F. Lewis Chair in Nursing at the School of Nursing at Georgia State University in Atlanta and a spokesperson for the American Academy of Sleep Medicine, to get more insight about what these study findings mean for you and me.

The researchers asked 970 Copenhagen residents, men and women ages 30 to 60, “Do you often suffer from insomnia?” and if they had purchased prescription sleep medication in the last year. If the answer was “yes” to one or both questions, the participant was put into the “sleep disturbance” category. About 24% of participants were in this category. Those who answered “no” to both questions were the control group. Then each participant underwent a noninvasive eye examination called lens autofluorometry, which measured how yellow their eye lens was.

From past studies, the researchers already knew that eye lenses tend to become yellow as people age — it’s actually a type of cataract — and they also knew that sleep disturbances are more common among the elderly, so their goal was to see if there was a link between the two. In comparing the results of the eye exams with the incidence of sleep problems, researchers found that the more severe the yellowing of the eye lens, the higher the risk for sleep disturbances.

Dr. Decker explained that the yellowing of the eye lens prevents blue light — a type of light that we absorb from short wavelength rays — from entering the eye. That can be problematic, because blue light can alter your circadian rhythms by influencing the release of melatonin, a hormone that tells your body when it’s time to be sleepy. In other words, the more yellow your eye lens becomes, the less blue light your eye absorbs, which changes the patterns of melatonin released in your brain — and therefore, the less restful sleep you’re likely to get. It turns out that what happens in broad daylight every day may have a profound effect on what happens in your pitch-black bedroom every night.

More than eight out of 10 cases of sleep disorders go undiagnosed, Dr. Decker observed, and that is quite troubling when you consider that not sleeping well can seriously impair quality of life and undermine health. So if you suffer from insomnia for more than 30 days, it’s important to see a sleep specialist who can get to the bottom of your problem — and help you find a solution.

If you’re suffering from insomnia, you may also want to schedule an appointment with an ophthalmologist — especially if you are having classic cataract symptoms, such as decreased night vision, glare and halos, decreased vision in very bright light or an inability to see 20/20 with a new pair of glasses. A cataract is not easily detected with the naked eye, because the lens yellowing occurs behind the iris — it usually is discovered only when an ophthalmologist uses a microscope. To find out more about how a yellowing lens might be treated, I called Brett Levinson, MD, an ophthalmologist in Baltimore and clinical instructor of ophthalmology at University of Maryland School of Medicine.

If a cataract is serious enough, it can be removed with surgery. During cataract surgery, your natural lens is replaced with an artificial lens that can transmit the full color spectrum. Of course, since this research on cataracts and sleep disturbances is new, there isn’t much proof — at least not yet — that removing a cataract will make sleep problems go away, so an ophthalmologist isn’t likely to remove yours (nor will Medicare pay for the surgery) unless it’s also impairing your vision.

In terms of fending off (or slowing down) this yellowing of the lens, doctors don’t know of much you can do just yet. But it helps to quit smoking (or don’t start), and make sure you eat a healthy diet and exercise regularly to help prevent diseases like diabetes and heart disease, because those diseases can make lens yellowing more rapid and severe. And, can you simply supplement melatonin to overcome what’s lost by a yellow lens? That is a question still to be studied, but worth asking your doctor.