Bilberry for Vision / Eye Health
Bilberry does not reliably improve vision: the strongest evidence shows no benefit for night vision in healthy people, and the only positive findings are small, industry-funded, and limited to subjective eye-fatigue symptoms. It is not a substitute for routine eye care.
Why this grade7-layer evidence engine
The grade is weak (Tier C) because the evidence is thin and points in opposite directions. The strongest source, a systematic review of placebo-controlled trials (PMID 15530951), pooled four rigorous RCTs in people with normal vision and found the long-standing claim that bilberry sharpens night vision is not supported; all four high-quality trials were negative across every night-vision endpoint.
The positive signals are weak and indirect. A double-blind RCT in screen workers (PMID 25923485) reported only a modest drop in subjective eye-fatigue symptoms and a small flicker-fusion change, with no improvement in measured visual acuity; it was small, industry-funded, and low quality. A separate meta-analysis (PMID 28825651) confirmed anthocyanins can improve blood-vessel function, but its authors stress this circulatory effect is the proposed, not proven, route to any eye benefit.
Authorities mirror this uncertainty rather than endorse the supplement. The US FDA has engaged bilberry only through warning letters against unproven eye claims, and EU regulators authorise no vision health claim. The WHO monograph lists ophthalmic use only within a traditional-medicine framework, while NIH and major clinics stay cautious or silent. Heavy industry funding behind the positive trials and a possible blood-thinning interaction further lower confidence.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.425
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status