Vitamins for Macular Degeneration

Take these or go blind. Well, that’s not exactly the way they say it, but it is the underlying message. Various oral vitamin supplements are advertised for “ocular health”, particularly for age-related macular degeneration (AMD), which is a leading cause of blindness.

The source of this advice is the Age-Related Eye Disease Study (AREDS), which was sponsored by the National Eye Institute and Bausch and Lomb. A total of 3640 patients with AMD at various stages were randomized to: (1) antioxidants at 5-15 times higher than the recommended daily allowance (vitamin C 500 mg, vitamin E 400 IU and beta carotene 15 mg), (2) zinc oxide 80 mg plus cupric oxide 2 mg, (3) antioxidants plus zinc and copper or (4) placebo. The primary endpoints were progression to advanced AMD and moderate loss of visual acuity (3 or more lines of vision).

After 5 years of treatment, no benefit was seen in 1063 patients who joined the study with only early signs of AMD and good vision in the eye with more advanced disease. When these patients were excluded from the analysis (a predefined design variable), the estimated probability of progression to advanced AMD among the remaining patients was 28% with placebo, 23% with antioxidants alone, 22% with zinc alone, and 20% with both zinc and antioxidants. The estimated probability that at least 3 lines of vision would be lost at 5 years in at least one eye was 29% with placebo, 26% with antioxidants, 25% with zinc and 23% with both zinc and antioxidants. Only the combination of zinc and antioxidants had a statistically significant treatment effect compared to placebo (Archives of Ophthalmology 2001; 119:1417).

That combination is not necessarily harmless. In 2 prospective double-blind trials, long-term use (5-8 years) of a high dose (20 mg) of beta carotene in male smokers was associated after 18 months with an increased incidence of lung cancer and death (New England Journal of Medicine, 1994; 330:1029; New England Journal of Medicine 1996; 334:1150). And some studies have suggested that vitamin E, particularly in doses > 400 mg/day, may increase all-cause mortality (Annals of Internal Medicine 2005; 4:142). Bear in mind that some patients who take antioxidants to prevent AMD may be taking other multivitamin preparations as well.

A prospective, randomized trial of a new formula (AREDS 2) is in progress (Ophthalmology 2012; July 26.epub). Even though no results are expected before 2013, PreserVision Eye Vitamin AREDS 2 Formula  (Bausch & Lomb), which differs from the original AREDS formula in substituting lutein and zeaxanthin for beta-carotene, has already been marketed as the only formula proven to slow the progression of moderate-to-advanced AMD.

There are no data suggesting any benefit from these vitamins or antioxidants in patients who do not have AMD or have only mild disease. The magnitude of the benefit from the AREDS1 formula in AMD patients with moderate or severe disease was modest, to say the least. There is no evidence yet, unless Bausch and Lomb has some way of predicting the future, that the AREDS2 formula offers any benefit for anyone.

The November issue of Treatment Guidelines will discuss these medications and others for treatment of AMD and other diseases of the eye.

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