Bilberry extract has one of the more specific, citable clinical findings of any ingredient in VisiFlora's formula — separate from a much older myth worth clearing up first.
You've probably heard that WWII fighter pilots ate bilberry jam to sharpen their night vision before missions. This story is widely repeated in supplement marketing but has no solid historical sourcing — it's considered supplement-industry folklore, not a verified historical fact. We flag it explicitly because separating real research from repeated anecdote is central to how we write every page on this site.
A 2020 randomized, double-blind, placebo-controlled trial published in Nutrients is more useful. Researchers recruited 109 healthy adults aged 20–60 who worked with visual display terminals and reported eye fatigue symptoms. Half received 240mg of standardized bilberry extract daily; half received placebo, for 12 weeks. The measured outcome was ciliary muscle contraction — the muscle responsible for shifting focus between near and far objects — using a specific optical measurement (HFC-1). Results showed statistically significant improvement in the bilberry group at both week 8 (p=0.014) and week 12 (p=0.017) compared to placebo [1].
The effective dose in this trial was 240mg/day of standardized bilberry extract, taken consistently for at least 8 weeks before a measurable difference appeared. See our VisiFlora ingredients page for how bilberry fits into the full formula.