 Clinical evidence for effects of plant anthocyanins on vision, and particularly night vision is controversial. Two clinical trials were conducted to investigate whether blueberry juice consumption affected visual dark adaptation, functional night vision, and recovery after photo-bleaching of the retina. One trial S2 employed a 3 week intervention and washout period, and two doses of blueberries plus a placebo. The other trial L1 employed a 12 week intervention plus an 8 week washout and tested one blueberry juice dose against a juice placebo. 