Macular Pigment Density and Distribution: Comparison of a Mimimum Motion Method with Autofluorescence

Abstract

Abstract: : Purpose: To assess inter-subject variability in macular pigment (MP) distribution and to determine whether autofluorescence (AF) imaging can be used to assess the distribution and amount of human MP. Methods: 15 subjects had their MP distribution profiles determined using a Moreland anomaloscope modified for motion photometry. Optical density was measured at 13 retinal locations and calculated relative to the mean value between 5-7 degrees eccentricity. The effects of using less eccentric reference locations were simulated. 6 of these subjects additionally underwent AF imaging using a scanning laser ophthalmoscope and MP profiles of AF images were compared with the psychophysically determined MP distribution profiles. Results: Peak optical density varied between 0.1 and 0.8 and correlated poorly with the lateral extent and distribution of MP, both of which varied unpredictably between subjects. MP peak optical density was underestimated by up to 40% in some subjects when calculated relative to a reference location at 4 degrees. Comparison of psychophysically derived profiles of MP distribution with grey-scale profiles of AF images revealed close point by point correlation. Conclusions: The shape and lateral extent of macular pigment distribution (and therefore ammount) varies between subjects and cannot be predicted from the peak optical density. Pychophysical assessment of optical density may be influenced by the lateral distribution of MP if the reference location lies within the pigmented area. Autofluoresecence imaging provides a fast objective method for assessment of macular pigment density and distribution in vivo.

Keywords: 462 macular pigment • 308 age-related macular degeneration • 337 carotenoids/carotenoid binding proteins