Vitamin A for Dry Eye Disease
Verdict: Published with Warning
Across 4 PubMed studies, the evidence for Vitamin A in Dry Eye Disease grades Tier C — weak evidence. Effective, but with safety or population caveats.
C 🟠 C Weak Evidence Published with Warning
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.52
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
C · Published with Warning
Confidence
86%
Highly consistent evidence
Evidence level
E6
Multiple smaller RCTs (n<500)
▸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 = 0.518
- 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 + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (4)L2 · primary research & systematic reviews
A comparison of vitamin A and cyclosporine A 0.05% eye drops for treatment of dry eye syndrome
Finding: Topical vitamin A eye drops significantly improved blurred vision, tear-film BUT, Schirmer I and impression cytology versus artificial-tears control (all P<0.05) and performed comparably to cyclosporine A 0.05%, with the Schirmer increase reaching significance at 2 and 3 months.
View on PubMed Efficacy and safety of retinol palmitate ophthalmic solution in the treatment of dry eye: a Japanese Phase II clinical trial
Finding: Topical retinol palmitate produced a significantly greater reduction in rose bengal staining at 2 and 4 weeks (P<0.05 and P<0.01) and better fluorescein clearance at 4 weeks (P<0.05) with no excess adverse events, but several other tear-film and symptom endpoints did not differ from placebo.
View on PubMed Effects of short-term oral vitamin A supplementation on the ocular tear film in patients with dry eye
Finding: In the dry-eye group oral vitamin A significantly improved tear ferning grade (2.4 to 1.4; P=0.01) and tear osmolarity (293.0 to 303.0 mOsm/L; P=0.01) but did NOT change TBUT (P=0.49) or PRT (P=0.17), and produced no significant change in healthy controls; no clinical symptom endpoint was assessed.
View on PubMed A randomized, double-blind, placebo-controlled study of oral antioxidant supplement therapy in patients with dry eye syndrome
Finding: The combined antioxidant supplement (which included vitamin A) significantly improved TFBUT at week 4 (4.70 vs 3.41 s; P=0.010), Schirmer at week 8 (7.79 vs 5.72 mm; P=0.027) and subjective improvement (70% vs 34.8%; P=0.021), but vitamin A's individual contribution cannot be isolated from the multi-ingredient formula.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
Vitamin A — GRAS — 21 CFR 184.1245, 184.1930 — Technical Effect: NUTRIENT SUPPLEMENT — SCOGS no. 118 source↗
L4b EU EFSA
Neutral
Vitamin A contributes to the normal function of the immune system; Vitamin A contributes to the maintenance of normal vision; Vitamin A contributes to the maintenance of normal skin; Vitamin A contributes to the maintenance of normal mucous membranes; Vitamin A has a role in the process of cell specialisation; Vitamin A contributes to normal iron metabolism. source↗
L4c UK NHS
Cautious
Do not take cod liver oil or any supplements containing vitamin A (retinol) when you're pregnant. Too much vitamin A could harm your baby. source↗
L4d TW TFDA / 衛福部
Neutral
維生素A 指示藥每日用量上限 10,000 IU（3,000 微克 RE）；換算：1 微克 RE = 1 微克 Retinol = 6 微克 β-Carotene；3 微克 RE = 10 IU。 source↗
L4e WHO
Supportive
In settings where vitamin A deficiency is a public health problem, vitamin A supplementation is recommended in infants and children 6-59 months of age as a public health intervention to reduce child morbidity and mortality (strong recommendation). source↗
L5a NIH Office of Dietary Supplements
Supportive
The most common clinical sign of vitamin A deficiency is xerophthalmia, which develops after plasma retinol has been low. The first sign is night blindness, or the inability to see in low light or darkness as a result of low rhodopsin levels in the retina. source↗
L5b Mayo Clinic
Cautious
Lack of vitamin A may lead to a rare condition called night blindness (problems seeing in the dark), as well as dry eyes, eye infections, skin problems, and slowed growth. For xerophthalmia (eye disease), the dose is oral, 7500 to 15,000 RE (25,000 to 50,000 Units) a day. Claims that vitamin A is effective for treatment of conditions such as eye problems not caused by lack of vitamin A have not… source↗
L5c Cleveland Clinic
Supportive
Your healthcare provider will recommend vitamin A supplements. Your provider may also suggest using artificial tears and topical antibiotics if you have an infection. source↗
L5d Harvard Health
Cautious
Limited research suggests that other potentially effective treatments for dry eye syndrome include: oral antioxidant supplements, topical vitamin A, sodium hyaluronate applied to the eye, topical glucocorticoids (although only for short term use and under the supervision of an ophthalmologist given the potential for significant side effects), omega-3 and omega-6 fatty acids, acupuncture. source↗
L5e Specialty Society (condition-mapped)
Cautious
vitamin A (retinyl palmitate), showed significant effects in improving blurred vision, TBUT, Schirmer score, and impression cytology findings in subjects with DED. However, vitamin A metabolites are also known to cause MGD in animal models, including glandular keratinization and atrophy, reduced quality of meibum, reduced tear film break up time, increased tear film osmolarity, and dry eye symp… source↗