Dr Newsome's response to our study1 points out the need to clarify a few methodologic issues.First, in response to Dr Newsome's query about the time of blood drawing: the purpose of this study was to determine whether high plasma levels of antioxidants protect against age-related macular degeneration. A major limitation in the studies cited by Dr Newsome is that the blood levels of the antioxidants were assessed concurrently with the determination of age-related macular degeneration status. Concurrent determinations tell us little about the antioxidant status of participants prior to the development of age-related macular degeneration, which may be the relevant period for a protective effect. Thus, we believe that our collection of serum samples 2 or more years before the assessment of macular status in 82% of the study population is a methodologic advantage and lends more credence to our observations. As we state in our
West SK, Bressler SB, Bressler NM, Vitale S. Are Antioxidants or Supplements Protective for Age-Related Macular Degeneration?-Reply. Arch Ophthalmol. 1994;112(6):730. doi:10.1001/archopht.1994.01090180027008
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