Light exposure and macular pigment optical density.
OBJECTIVE
Biochemical research has demonstrated that lutein and zeaxanthin, the two macular carotenoids, are bleachable pigments. Further, evidence suggests that exposure to UV light can degrade plasma carotenoid levels in vivo. The present study investigated the effects of exposure to normal levels of light on the levels of lutein and zeaxanthin in the retina.


METHODS
The optical density of macular pigment (MPOD) was measured in two male subjects under four different light-adaptation conditions for 20 days. Heterochromatic flicker photometry was used to measure MPOD at 0.5 degrees eccentricity.


RESULTS
The four conditions of light adaptation did not significantly affect MPOD. As in previous studies, however, a significant day-to-day difference was observed for both subjects.


CONCLUSIONS
The results suggest that lutein and zeaxanthin levels in the eye are unaffected by light and oxidation throughout the day. This justifies current research methods in which MPOD measures are made regardless of the time of day. However, significant between-day variance indicates that multiple MPOD measures may be necessary to evaluate lutein and zeaxanthin levels in the retina accurately.
Wenzel
Adam J
AJ
Department of Psychology, University of New Hampshire, 10 Library Way, Durham, NH 03824-3567, USA.
Fuld
Kenneth
K
Stringham
James M
JM
D000221:Adaptation, Ocular; D000328:Adult; D006801:Humans; D008027:Light; D014975:Lutein / Q000378:metabolism; D008297:Male; D012160:Retina / Q000378:metabolism / Q000528:radiation effects*; D012168:Retinal Pigments / Q000378:metabolism*; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000378:metabolism
D012168:Retinal Pigments; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene; D014975:Lutein