Artikel
Macular pigment: Methods of analysis, evidence-based data and prognostic implication
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Autoren
Veröffentlicht: | 22. September 2004 |
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Gliederung
Text
Objective
Low levels of macular pigment (MP) are supposed to represent a potential risk factor for development of age related macular degeneration (AMD). Which Methods of investigation of MP are available for clinical use? Is the MP concentration associated with the risk for the development of AMD? Do these investigations result in an individual risk profile? Can we advise supplementation of lutein and zeaxanthin according to these data?
Methods
Fundus autofluorescence (AF) mapping is performed employing 488nm (absorbed by MP) and 514nm (no absorption by MP), digital substraction of the log AF images and quantitative analysis of grey scale values in the resulting MP density maps.
Results
Analysis of AF can easily be performed within clinical practice. Data of one and two wavelengths methods show a good correlation (Rsquare 0,7). A second wavelength not absorbed by MP and computerised alignment of both maps takes into account the inhomogeneous distribution of fluoropohores in the central retina and therefore provides more accurate values. Furthermore falsification of grey scale values caused by irregular illumination and also by local drusen, PE atrophy, PE-proliferation can be minimised using a second wavelength.
In recent clinical studies the distribution of MP shows strong interindividual variations. Reduced levels of MP were significantly more often observed in the AMD group. Fellow eyes of geographic atrophies showed the lowest central MP values. Oral supplementation of lutein and zeaxanthin may influence this potential risk factor.
Conclusions
AF imaging and analysis of grey scale values in MP density maps can easily be performed in everyday practice to create an individual risk profile and to facilitate follow-up investigations. This strategy of quantitative MP analysis on AF images is used in clinical studies and can propose a prognostic role of the MP concentration as a potential risk factor for AMD. First results of a supplementation study with lutein and zeaxanthin are presented.