Doc: Yellow lenses to the rescue for macular degeneration
Dear Dr. Roach: I have an elderly friend who’s becoming blind from macular degeneration. After hearing of a particularly frustrating event she experienced due to vision loss, I remembered the great clarity that the yellow-lens (to reduce glare) glasses gave me, not just at night, but daytime also.
So, I sent her a pair to see if it would help, as a last-ditch effort. She called me crying, it had made such a difference! She has now had her prescription eyeglasses done with the yellow (blue-canceling?) lenses. Of course, we understand that this is just a temporary help, and won’t prevent the blindness from taking its course, but it has given her much better vision for a time.
Dear I.L.B.: Age-related macular degeneration is the leading cause of vision loss in industrialized countries. It is a degeneration of the central part of the retina, called the macula, which is responsible for fine detail central vision. The underlying cause is not precisely known, and the course is progressive.
I was able to find a 2002 study that confirmed that yellow or orange lenses improved contrast sensitivity in people with early age-related macular degeneration, whereas red and gray lenses worsened it. Another study suggested that the perceived benefit (the subjective experience by the person) was enhanced, but that objective improvement in vision was not actually improved much at all.
In my opinion, perceived benefit is still worth a great deal, and since there is little effective treatment for the more common “dry” form of ARMD beyond vitamins and smoking cessation, I am publishing your letter in hopes that some people will get improvements in their vision, as your friend did, from this low-cost treatment with essentially no risk of side effects.
Dear Dr. Roach: I am 87 and take 10 mg of melatonin every night to help me sleep. I have heard it is perfectly safe. Are there any side effects to melatonin? I know a lot of people who take it, including one child who takes 3 mg.
Dear B.D.: Melatonin is a hormone secreted in the pineal gland of the brain that affects sleep and circadian rhythms. At nighttime, melatonin blood levels are 10 times higher than in the day. Melatonin is used extensively as a sleep aid, as you can confirm.
There is no substance you can put in your body that is perfectly safe at all doses. To paraphrase a wise man, anyone who tells you differently is selling something. However, the risk of major side effects with even high doses of melatonin is low. The major adverse events reported were headache, fragmented sleep and seizures. Rare adverse events reported included confusion, psychosis, autoimmune hepatitis and rash.
Incidentally, the term “side effect” means an unintended effect that occurs from a drug when taken correctly. “Adverse event” refers to any undesired reaction that comes with taking a medication. Adverse events are more common at high doses. With very high doses of melatonin can come additional types of reactions, including poor memory and reduced physical exercise performance.
Ten mg is far more melatonin than I recommend starting with. For older people, I recommend 0.5 mg to 1 mg about an hour before bed. Higher doses are generally not more effective and have higher risk.
Readers may email questions to ToYourGoodHealth@med.cornell.edu