#25: Advances in Dry
AMD Studies
Because it is less immediately vision threatening than wet age-related macular degenera- tion (AMD), the treatment of dry AMD is typically less aggressive and has not been as thoroughly studied. The publication, however, of the AREDS and AREDS-2 trials in 2001 and 2013, respectively, had significant impact by showing that the use of antioxidants and zinc can slow the progression of dry AMD.

In the AREDS trial, patients were randomized to treatment in 1 of 4 treatment groups: an antioxidant group (vitamin C 500 mg, vitamin E 400 IU, beta-carotene 15 mg); zinc (zinc oxide 80 mg/cupric oxide 2 mg); antioxidants plus zinc; or placebo. Results showed that the use of zinc plus antioxidants lowered the risk of progression to advanced AMD or visual loss in patients who had baseline moderate or advanced AMD.

Because of the link of beta-carotene and high-dose vitamin E to a variety of adverse events, however, the AREDS-2 trial was un- dertaken with these goals:

To see if the addition of further antioxidants—specifically lutein and zeaxanthin (carotenoids), and docosahexaenoic and eicosapentaenoic acid (antioxidants)—to the AREDS vitamin formulation would further decrease risk of AMD; and
Whether eliminating beta- carotene and lowering the dose of zinc would impact efficacy.

Results of the trials showed that there was no additional benefit of adding further antioxidants to the AREDS regimen. Never- theless, replacing beta-carotene with the combination of lutein and zeaxanthin led to a slight reduction in the risk of progression to advanced AMD with no increased risk of lung cancer. This is of particular relevance in smokers with AMD.

Another recent advance in dry AMD in- volves the use of autofluorescence to track the progression of geographic atrophy. The important of autofluorescence findings in areas with geographic atrophy due to AMD was initially outlined in the Geographic At- rophy Progression Study and continues to be researched.