Abstract
Abstract: :
Purpose: Macular Pigment (MP) reduces oxidative damage in the central retina by absorption of blue light and direct antioxidative properties. Its concentration can be measured by flickerphotometric analysis of MP optical density and also by central absorption of MP on autofluorescent (AF) images. Differences in MP distribution could be documented quantitatively. The purpose of the present study was to analyze the association of different MP concentration and distribution as specific risk factors for different types of late AMD. Patients and Methods: AF images (HRA) were analyzed with optical density profile analysis (MPOD) in respect to the peak, total MP and the central/total-ratio (C/T-ratio) of AF absorption caused by MP in 340 eyes of persons older than 60 years (174 male, 226 female, mean age 72y). Of these eyes 91 were normal (co-gr.; 60-87y, mean 70.3y) and 249 eyes with early AMD (AMD-gr.; drusen, RPE-proliferation or atrophy, 60-89y, mean 71.1y); 154 patients with early AMD had late AMD in the fellow eye (13 geographic atrophy (GA); 22 serous PED with or without occult CNV (PED); 119 occult or classic CNV (CNV)). Results: Comparing the MP distribution between the co- and the AMD-gr. the four types of MP distribution (type 1 intense central and paracentral MP, peak MPOD 0.65, type 2 less intense central and paracentral MP, peak MPOD 0.42; type 3 only central MP, peak MPOD 0.42, type 4 only paracentral MP, peak MPOD 0.29, p<.0001) demonstrated type 2-4 with lower MP more often in the AMD-group (p<.0001). Also the mean MP peak (0.61 versus 0.53, p=.03), the total MP (p<.01) and the C/T-ratio (p<.001) was lower in the AMD-gr. The presence of atrophic spots in the study eye was associated with type 4 and low C/T-ratio. Differentiating the AMD eyes by late AMD in the fellow eyes GA was associated with type 4 and lowest C/T-ratio (p<.01), while MP values of CNV and PED were comparable to the whole AMD group. Conclusions: Variation from the common distribution of MP is associated with early AMD. Especially a reduced central MP (type 4) and low C/T-ratio is associated with atrophic spots and GA in the fellow eye. Therefore the analysis of the peak concentration and distribution of MP can identify persons with higher risk for the development of early AMD and specific types of late AMD. Because persons with very low C/T-ratio appear at high risk of developing GA, this may have specific pathogenetic implications towards oxidative damage as factor involved in the development of GA.
Keywords: macular pigment • age-related macular degeneration • image processing