Authors: Filippello Massimo, Scilio Cristina, Filippello Giulia, Cristaldi Martina, Spampinato Giorgia, Rusciano Dario.
The rationale of this study stems from the consideration that vision is a dynamic process, during which photopigments of photoreceptor cells (rods and cones) are continuously consumed and regenerated by retinal pigmented epithelial (RPE) cells. The whole process of vision triggered by light radiation generates free radicals which are potentially toxic to the cells in the central retina (macula), which is the main player in vision. Therefore, the central retina contains carotenoid pigments (mainly lutein and zeaxanthin) with the double function of shielding the cells from light radiation and providing free radical-scavenging action due to their antioxidant power. Nonetheless, visual performance (including visual acuity, contrast sensitivity and stereoscopic perception) can be hampered by bright light and by sudden changes in illumination conditions, such as during the transit from the dark to intense light. Therefore, objective of this study has been to investigate whether the treatment with a food supplement regimen containing different antioxidant and protective elements shown to protect from photo-oxidative damage retinal pigment epithelial (RPE) cells, might also improve retina functions during challenging light conditions. We present here our findings, showing the protective effects on human RPE cells in vitro of lutein and cyanidin-3-glucoside (C3G) against photo-oxidative stress. Accordingly, the results of a retrospective analysis of a case series show that sport motorcycle test pilots (who need for their profession an optimal visual performance) taking a commercially available food supplement containing a blend of antioxidant and protective molecules (lutein, C3G, verbascoside and zinc), improved their visual abilities and reduced their sensibility to glaring lights in a dose/time-dependent fashion. In conclusion, these results suggest that a food supplement may increase the antioxidant defense of the retina, thus improving the visual performance also during challenging illumination conditions, hence increasing the safety of individuals finding themselves in such situations.
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