Longitudinal studies of macular pigment distribution profiles assessed by minimum motion photometry and fundus autofluorescence

Abstract

Abstract: : Purpose:To monitor the variability of macular pigment (MP) distribution profiles measured over several years using minimum motion photometry and fundus autofluorescence Methods: Four subjects with significantly different macular pigment distribution profiles were monitored over periods of 2–5 years. MP optical density profiles were obtained using motion photometry (grating components 460nm and 580nm). Optical density values were computed at 12 retinal locations relative to the most eccentric setting at 7 degrees eccentricity. Fundus autofluorescence images were obtained through a high–pass barrier filter using a modified scanning laser ophthalmoscope (488nm radiation). MP profiles derived from calibrated grey–scale analysis of fundus autofluorescence images were made repeatedly in three of the four subjects and at the same retinal eccentricities as for motion photometry. Results: Peak optical density and the shape of the MP distribution showed a high degree of stability in all subjects. The mean MP optical density at the fovea ranged between subjects from 0.1–0.8 and the standard deviation of measurements at fovea over the time period ranged from 0.05–0.11. The largest standard deviation at 1 degree eccentricity (0.42 + 0.12) was seen in a subject monitored over 6 years. Analyses of fundus autofluorescence images were also carried out and MP distribution showed a high degree of stability in all subjects with a maximum measurement SD at the fovea of 0.08 and at the parafovea of 0.04. Conclusions: MP, monitored over an extended period, shows a high degree of stability in terms of peak OD and shape of the distribution profile. Psychophysical assessments of MP optical density correlate well with values derived from fundus autofluorescence images.

Keywords: macular pigment • carotenoids/carotenoid binding proteins • age–related macular degeneration