Samuel M. Liu, MD, PhD is the Director of Retina Services at Princeton Eye Group. He sees consultations for all types of retinal diseases, and has provided us with a summary of the latest updates on the treatment of macular degeneration.
There are two main types of age-related macular degeneration (AMD). The ‘dry’ form of AMD results in the degeneration of nerve cells in the center of the retina (the macula). There is no cure for this atrophy, but generally speaking, the process is usually slowly progressive. At this time, the only option for possibly slowing down this type of degeneration is the use of anti-oxidant vitamins.
In 2006, the first Age-Related Eye Disease Study (AREDS) led by the National Institutes of Health found that patients taking the original AREDS supplement formulation — 500 mg of vitamin C, 400 IU of vitamin E, 80 mg of zinc, 15 mg of beta-carotene, and 2 mg of copper — were 25% less likely to progress to advanced AMD than patients who received a placebo. There was additional evidence outside of the trial that suggested that diets high in lutein, zeaxanthin, and omega-3 fatty acids might reduce progression of AMD. For this reason, a second large multi-center trial was commenced, named AREDS2. Other research suggested that beta-carotene, which was part of the original AREDS formula, might increase the risk of lung cancer in smokers, so it needed to be studied more carefully. The dosage of zinc also was examined in AREDS2. There was concern that the 80-mg dose of zinc in the original study might place some patients at risks of side effects.
In 2013, the AREDS2 Study Group released their first conclusions. Although the study design was complex, essentially AREDS2 discovered that those who took an AREDS formula with lutein and zeaxanthin but no beta-carotene, reduced their risk of AMD progression by about 20%, compared with participants who took an AREDS formulation with beta-carotene but no lutein or zeaxanthin. This particular sub-group’s results were especially notable, because the removal of beta-carotene from the recommended AREDS formula would also reduce the potential for increased lung cancer risk in previous or current smokers with AMD. Since the release of the AREDS2 data, Dr. Liu’s recommendations for AREDS vitamin supplements are as follows:
- No evidence of AMD on examination: Dr. Liu recommends a diet rich in green, leafy vegetables and omega-3 fatty acids, supplemented with a daily multivitamin.
- Evidence of early or moderate AMD on exam: Dr. Liu recommends the same healthy diet and multivitamin, supplemented with an AREDS2 formula vitamin containing lutein and zeaxanthin.
- Evidence of advanced AMD on exam: Dr. Liu does not recommend adding an AREDS vitamin, because this has not been shown to prevent progression in either of the AREDS studies.
For patients who have never smoked and are taking an original AREDS vitamin supplement, Dr. Liu recommends continuing to take the original formula, based on their lower risk of lung cancer as nonsmokers, and the longer clinical track record of the original AREDS formula. In most cases, the cost of the original formula vitamins is also less than the newer formula.