Abstract
Purpose::
In a majority of subjects observed in the LUNA study supplemental lutein (L) and zeaxanthin (Z) resulted in an increase of macular pigment (MP) optical density at an eccentricity of 0.5° (MPOD0.5°). With the present analyses we intend to detect possible changes of patterns of MP distribution especially at a more eccentric location.
Methods::
Retinal (by 2-wavelength autofluorescence method) and serum (HPLC) response to 6 months supplementation with 12mg esterified Lutein (L) and 1mg esterified Zeaxanthin (Z) (n=108, 92% afflicted with AMD) were investigated on five occasions during the period of supplementation, and once again 3 months following discontinuation of the supplement. Central and eccentric changes of MPOD are investigated.
Results::
Following supplementation of L and Z the MPOD values increased up to three months after stop of intake (visit 6). Mean increment was 0.1 optical density units (ODU) (min.-0.14 max.+0.35)at 0.5° and 0.02 ODU (min.-0.05 max +0.11) at 2°, respectively. Increment of MPOD at 0.5° was related with that at 2° with r=0.407, p<0.0001. In five subjects neither at 0.5° nor at 2° eccentricity MPOD increased, four subjects accumulated MPOD at 2° only, and in seven subjects MPOD0.5° but not MPOD2° increased. Based on the differences (MPOD0.5or2°[visit 6]-MPOD0.5or2°[baseline]) we classified subjects into quartiles, in terms of MPOD response at 0.5° or 2°, respectively. Subjects with low baseline MPOD0.5° were more likely to exhibit a dramatic, or to exhibit no rise in MPOD0.5°. Despite one quartile without detectable increment of MPOD0.5°, the other quartiles reached similar levels of MPOD0.5° at visit 6. The strongest increment of MPOD2°, however, was detected in subjects with highest MPOD2° at baseline, the other quartiles started with similar MPOD2° and finished with divergent values.
Conclusions::
Based on these and earlier findings we presume that different patterns of MP distribution exist and may be a result of individual local metabolism. In some of these patterns the MPOD accumulates only or especially in the centre and in others only or especially in a more paracentral location. While after 6 months of supplementation at 0.5° the values reached a saturation level, at 2° no such saturation could be observed. Future analyses of the MP patterns will have to be performed to investigate whether the distribution- more than the total amount- of MP plays a role in prevention of AMD.
Keywords: macular pigment • clinical (human) or epidemiologic studies: risk factor assessment • age-related macular degeneration