Comparison between Macular Pigment Optical Density Measurements Using Two-Wavelength Autofluorescence and Heterochromatic Flicker Photometry Techniques

Abstract

The association of macular pigment (MP) with age-related macular degeneration has been extensively studied in recent years, and interest in a rapid, objective, and accurate technique to measure MP optical density (MPOD) has increased. The purpose of this study was to compare the MPOD values at specific loci around the fovea using the heterochromatic flicker photometry (HFP) and the two-wavelength autofluorescence (AF) methods in a young, healthy population. Ten patients (20 eyes) were enrolled. Subjects with any ocular or systemic disease were excluded. All patients underwent HFP and AF examination. The AF examination was performed using a modified scanning laser ophthalmoscope. Values for both devices were measured at four eccentricities around the fovea (0.25 degrees , 0.5 degrees, 1.0 degrees, and 1.75 degrees). Each eye was tested three times with each Statistical analysis was based on paired t-test and linear regression analysis. At all retinal eccentricities, the HFP values were consistently lower than the HRA values (P < 0.001). There was, however, a significant correlation at almost all locations. The strongest correlation between two methods was found at 1.75 degrees from the center of the fovea (r = 0.73). The modified-HRA AF method for MPOD generated results that were highly correlated with the standard HPF method but consistently higher at all eccentricities. These findings suggest that HRA can be reliably used in patients unable to perform HPF, which is important for wider clinical application of MP testing.