AAO’s assessments of alternative therapies sound a cautious note

The Academy’s Complementary Therapy Assessments question the value of antioxidants for AMD, dismiss an electrical stimulation technique.

In recent years, with heightened interest among the public in alternative or complementary therapies, many patients have come to ophthalmologists’ offices with inquiries about therapies on the peripheries of ophthalmological science.

With limited numbers of clinical trials published, ophthalmologists are often at a loss as to how to advise patients on these treatments.

Because of the lack of information available, the American Academy of Ophthalmology (AAO) has issued a series of Complementary Therapy Assessments (CTAs), short papers reviewing what has been published about the safety and efficacy of alternative treatments. These reports are designed to help physicians give advice to patients.

Four CTAs issued last year address issues that have been recently in the news in ophthalmology.

Two of last year’s CTA reports cover what is known about the efficacy of antioxidant supplements in age-related macular degeneration (AMD) and in cataract prevention. A third dismisses the efficacy of a technique called microcurrent stimulation for AMD. A fourth defers judgment on the efficacy of a technique called apheresis for AMD.

Retinal specialist and AAO spokesman Herbert L. Cantrill, MD, who reviewed the contents of the CTAs in an interview with Ocular Surgery News, said the documents take a cautious, skeptical approach to these treatments that is sometimes missing in lay reports.

Antioxidants in AMD

One CTA, Dr. Cantrill said, covers the effects of antioxidants in AMD. According to some researchers, the CTA notes, oxidative damage to the retina caused by free radicals may lead to AMD, and antioxidants may neutralize the damage to retinal cells.

“There’s actually some experimental information that these vitamin supplements can boost levels of antioxidants in the blood,” Dr. Cantrill said.

According to the CTA, however, the role of antioxidants in the prevention of AMD is currently unknown. Without randomized trials demonstrating the effect of antioxidants, the AAO’s review of the literature did not not find support for the theory that the substances can be of benefit.

“I would say in general there’s a lot written about, a lot of hype about, a lot of commercials in regard to these vitamins and macular degeneration, but there probably isn’t a lot of sound, scientific evidence that they help,” said Dr. Cantrill.

However, Dr. Cantrill said he still occasionally recommends antioxidants to some patients.

“I’m actually kind of mildly in favor of them, but in a special way,” he said. “Certainly if you see a patient in their 40s or their 50s, who is relatively young and has some very early beginnings of macular degeneration, I would be pretty much be in favor of putting them long-term on the vitamins or talking about their diet,” Dr. Cantrill said.

Antioxidants naturally found in food include vitamin C, vitamin E, carotenoids, selenium and zinc.

“It turns out to be the dark, green, leafy vegetables,” Dr. Cantrill said. “One that is most readily available is spinach, and it can be cooked or raw or in any form. It could be okra, kale, mustard greens, turnip greens, those sorts of things.”

But Dr. Cantrill said he would not suggest the use of antioxidants for someone with advanced AMD.

“We have so many patients that are in their 70s or their 80s that already have well-established macular degeneration,” he said. “Say they have advanced disease. I can see no reason in the world why I would want to treat them with vitamins because basically the vitamins are going to work in a preventive fashion. They’re not going to have an effect on patients that already have well-established macular degeneration.”

Antioxidants in cataract prevention

A second CTA concerns the role antioxidants play in the prevention of cataracts. According to some, oxidative damage to cells may lead to cataract formation, the document says.

According to the CTA, several studies report that a lower risk of cataract is associated with higher serum levels of nutrients. Others report that no statistically significant association exists between cataract prevention and these nutrients. These inconsistencies have made it impossible for the AAO to make evidence-based recommendations for patients to use antioxidants, the document says.

Two randomized double-masked studies done in rural China, the document notes, do provide evidence for an effect of antioxidants on nuclear cataracts. According to the CTA, individuals between 65 and 74 years old who took multivitamin and mineral supplements had a 36% decrease in nuclear cataract incidence compared to controls, while those who took riboflavin and niacin had a 44% reduction compared to controls.

“First of all, we already have a good treatment for cataract, at least in the Western world,” Dr. Cantrill said. “It is true that on a worldwide basis cataract is a major, probably the number one cause of blindness. But it’s a multifactorial condition, it’s not just dietary, it’s genetic and environmental and a host of other factors. I would be very suspect of this study from rural China. It is true antioxidants probably play some role in the development of cataract but again, I think most people would emphasize the preventive role of the antioxidant.”

Microcurrent stimulation in AMD

Another CTA covers a technique in which electrical microstimulation is applied to nerve fibers to treat patients with AMD.

The report says the AAO does not support this form of therapy because strong scientific evidence has not been found to demonstrate the effectiveness of the procedure.

“That is a kind of a hoax,” Dr. Cantrill said. “It makes absolutely no sense whatsoever, and I think almost all physicians or ophthalmologists uniformly think it’s a hoax. It’s very expensive and I don’t think it does any good at all.”

The CTA lists significant financial danger as a risk involved with the microstimulation procedure.

For Your Information:

• Herbert L. Cantrill, MD, can be reached at 7760 France Ave., Ste. 310, Minneapolis, MN 55435; (952) 929-1131; fax: (952) 929-8873; e-mail: cantr002@gold.tc.umn.edu. Dr. Cantrill has no direct financial interest in any of the products mentioned in this article.

• The American Academy of Ophthalmology’s Complementary Therapy Assessments are available to download from the AAO’s Web site (www.eyenet.org/member/ops/quality/complementary.html) or via the AAO fax-on-demand service: (732) 935-2761; Antioxidant Supplements and Age-Related Macular Degeneration: FOD #1703; Antioxidant Vitamin and Mineral Supplements and Cataract Prevention and Progression: FOD #1705; Microcurrent Stimulation for Age-Related Macular Degeneration: FOD#1707.