Test–Retest Variability of Macular Pigment Optical Densitometry in the Elderly: Findings From the Health ABC ARMA Study

Abstract

Abstract: : Purpose: To determine the test–retest variability of macular pigment optical densitometry (MPOD) performed with a heterochromatic flicker photometry–based method in elderly subjects participating in the Dynamics of Health, Aging, and Body Composition (Health ABC) Age–Related Maculopathy Ancillary (ARMA) Study. Methods: MPOD was estimated with an LED–based instrument at 0.5 degrees of eccentricity from the fovea with an elderly–friendly technique requiring only 3 repetitions per target. MPOD test–retest variability was assessed in a sample of 53 subjects who had successfully completed a baseline MPOD session (age: 78.9 ± 3.5 yo; range: 69–85), including 13 subjects with early–stage ARM. Results: With our technique, there was excellent test–retest correlation (Pearson’s r coefficient: 0.853), and a coefficient of variation of only 15.41%. These figures are comparable to a recent study by Snodderly et al. (IOVS 2004;45:531–8) in elderly Mid–West women who were, on average, 66 years old (range: 50–79). Subjects with early–stage ARM performed similarly to normal subjects. Conclusions: These results confirm and expand the recent findings of Snodderly et al. and indicate that highly reproducible MPOD measurements can be obtained in elderly subjects even well into the 8th and 9th decade of life, when the risk of ARM is highest. Being affected with early–stage ARM did not diminish the reproducibility of the estimates. These reproducibility data indicate that MPOD measurements may be able to serve as an outcome measure in studies of macular health in elderly subjects and lutein supplementation trials in patients with ARM.

Keywords: aging • macular pigment • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology