Astaxanthin for Eye Fatigue / Digital Eye Strain
A few small, manufacturer-funded trials suggest astaxanthin may modestly ease subjective digital eye strain, but the evidence is too weak and conflicted for any health authority or eye-care body to endorse it.
Why this grade7-layer evidence engine
This earns a B (Preliminary Evidence) rather than a higher grade because the entire evidence base is about five small, short Japanese RCTs (n roughly 40-64, 4-12 weeks). They agree directionally: a 2025 children's trial reported a ~27% improvement in Computer Vision Syndrome Questionnaire scores (PMID 40014233), and the foundational Nagaki 2002 trial reported reduced asthenopia and improved accommodation amplitude. That consistency keeps it above the lowest tiers.
But quality is uniformly low. Every trial was funded by an astaxanthin raw-material or supplement maker (Fuji Chemical/AstaReal, BGG Japan, DHC, FANCL), often with company employees as named authors, creating heavy conflict-of-interest and publication-bias risk. Several positive results came from multi-ingredient formulas combining lutein, anthocyanin, or DHA (PMID 34376917; PMC4997915), so the benefit cannot be attributed to astaxanthin alone, and one healthy-adult trial found benefit only in the over-40 subgroup (PMID 36777084). Objective measures such as visual acuity and accommodation frequently failed to reach significance; mainly subjective questionnaires improved.
No independent authority backs this use. EFSA rejected the astaxanthin visual-acuity health claim for insufficient evidence; the FDA recognizes astaxanthin only as a food and color additive, not for any eye benefit; and NIH ODS, Mayo Clinic, Cleveland Clinic, and Harvard Health do not address it. No ophthalmology or optometry society endorses any supplement for digital eye strain, and no Cochrane-level review exists. For these reasons it is published with a warning.
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 = 0.575
- 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 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status