Effect of a Bilberry Extract(BILBERON®) —containing Diet on the Improvement of Eye Fatigue—related Symptoms(Ⅱ) ―A Randomized, Double—blind, Placebo—controlled, Parallel—group Comparison Study― Tingfu Liang and et al., 薬理と治療, 45, 1523-1534 (2017), DOI:http://dx.doi.org/