Age-related macular degeneration (AMD) and diabetic macular edema (DME) are two of the leading causes of vision loss in the United States. For patients dealing with these conditions, however, there is good news: a recent study re-affirms the value of a nutritional supplement in reducing the risk of developing advanced AMD. In addition, new medications offer expanded options for treating DME. Two Tufts Medical Center ophthalmology experts explain:
Preventing the Progression of AMD with an Easy-to-Use Supplement
Since a groundbreaking study was completed in 2001 establishing that daily high doses of vitamins C and E, beta carotene and minerals zinc and copper can help slow the progression of advanced AMD, some questions have arisen about a possible link between beta carotene and lung cancer in smokers. Additionally, some became concerned that the recommended high zinc dose could cause minor side effects like GI upset.
These uncertainties lead researchers to launch a follow up study called Age-Related Eye Disease Study 2 or AREDS2. Investigators sought to determine if the original AREDS formulation could be improved by adding omega-3 fatty acids; adding plant-derived antioxidants lutein and zeaxanthin; removing beta carotone; or reducing zinc. The results were just published this May in the Journal of the American Medical Association and provide helpful directives for physicians.
The study found that adding omega-3 fatty acids did not improve the AREDS formulation. They also found that lutein and zeaxanthin had no overall effect on AMD when added to the combination, but they were safer than beta carotene in patients who were former smokers. Lowering zinc also had no effect on AMD progression.
“Essentially, the second study had the same finding as the original AREDS study,” says Andre J. Witkin, MD ophthalmologist in the Vitreoretinal Disease and Surgery Service at the New England Eye Center (NEEC) at Tufts Medical Center, “which is that using the specific AREDS supplement reduces the risk of developing advanced age-related macular degeneration (AMD) in patients with moderate, dry macular degeneration in both eyes, or in patients with early or moderate dry AMD in one eye and advanced AMD in the fellow eye.”
The take-away message? Physicians should continue to recommend that patients with dry AMD take an AREDS supplement, either with beta carotene or modified to include lutein and zeaxanthin instead of beta carotene in patients who are current or former smokers.
New Anti-VEGF Medications Expand Treatment Armamentarium for DME
The ophthalmic complications of diabetes – including DME – are the leading cause of blindness in United States adults aged 20 to 74. All patients with diabetes are at risk of developing DME, and its prevalence approaches 30 percent in adults who have had diabetes for 20 years or more.
A decade ago, the standard of care for treating DME was the focal and grid laser. In fact, it was the only treatment option for DME. Today, however, with the availability of at least two anti-vascular endothelial growth factor (anti-VEGF) medications – and more in the pipeline – retinal specialists have a virtual armamentarium of treatment options to help patients achieve better vision.
“And for many patients, anti-VEGF medications are becoming the first-line treatment,” says Ophthalmologist Nadia Waheed, MD. “It’s a real paradigm shift.”
Another significant change in clinical practice is that the longstanding approach of waiting until DME becomes sufficiently severe before instituting treatment may no longer be appropriate in some cases.
“Since we now have other treatment options, we try to start treatment sooner versus later,” Dr. Waheed says. “We used to wait until the disease crossed a certain threshold, but there is evidence that if we start treating while DME is mild, we’re more likely to get a better response and visual outcome.”
Notably, Dr. Waheed was involved in the clinical trials that led to the development of the anti-VEGF drugs currently available and is currently working on trials for several other medications in development.
Are there fewer risks with the new medications compared to laser surgery? “There is very low risk with either procedure,” she notes. “But the clinical advantage of the anti-VEGF medications is that they do not cause small scars/blind spots in the macula. They can therefore can be used in cases where the edema involves the center of the macula, the fovea, and which is likely to cause the most visual symptoms. In contrast, lasering the fovea would cause a blind spot and loss of vision.”
What about the relative cost of each treatment option? “It depends on the medication used and the number of injections you need, but studies have shown that treatment with anti-VEGF medications is less expensive even when the more expensive drugs are used,” Dr. Waheed says.
She notes that while the anti-VEGF drugs are not a cure, most patients can expect stabilization and some can get improved vision. She emphasizes, however, that preventing DME – through good glucose, lipid and blood pressure control – remains the optimal strategy.
“Excellent diabetes control is the best way to prevent DME from happening in the first place,” she says. “And that is the best way to ensure you will maintain good vision through your lifetime.”