Bilberry for Eye Fatigue / Digital Eye Strain
Bilberry has only weak, disputed support for relieving digital eye strain: a handful of small trials report modest improvements, but no high-quality independent evidence confirms it works. It is not an established treatment.
Why this grade7-layer evidence engine
The entire human evidence base is four small, double-blind Japanese RCTs (n=20-109, 4-12 weeks), all pointing the same direction. The two best (PMID 25923485 and PMID 32106548) showed bilberry extract eased screen-induced declines in critical flicker fusion (p=0.023) and improved an objective marker of ciliary-muscle accommodation (p=0.014-0.017). But every trial was industry-funded, doses ranged five-fold with no dose-response, and two studies (PMID 34376917, PMID 22199129) bundled bilberry with lutein, astaxanthin or fish oil, so bilberry's own effect can't be isolated.
Crucially, there is no Cochrane review or large independent meta-analysis, and a 2022 ophthalmology systematic review of computer-vision-syndrome treatments found no high-quality evidence that supplements like bilberry help. That gap between consistent-but-small industry trials and absent independent confirmation is why the grade is weak and flagged as disputed.
Authorities reinforce the caution. The FDA has only issued warning letters to bilberry eye-supplement sellers for unproven disease claims; NIH/NCCIH calls it cautious, Mayo hedges, and Cleveland Clinic and Harvard Health do not address it for eye strain at all. An older 2009 WHO monograph lists ophthalmic uses, but it predates modern evidence standards. Bilberry may modestly soothe tired eyes for some, but proof of benefit is genuinely unsettled, and high doses carry antiplatelet/bleeding interactions.
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 = 0.494
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 1 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status