Vitamin D and Dry Eye Disease
Dry eye disease affects up to 30% of adults, more in women and older age. Vitamin D deficiency is more common in dry eye patients than controls; small supplementation trials show OSDI (Ocular Surface Disease Index) improvement. Vitamin D is a reasonable adjunct to standard dry-eye care.
Observational data
Bae 2016 (Korean nationwide survey) found 18% higher dry-eye odds in vitamin D-deficient adults after adjustment. Yildirim 2016 reported OSDI symptom improvement with vitamin D repletion in deficient dry-eye patients. Meta-analyses find modest overall benefit signal.
Mechanism
Vitamin D receptors expressed in the lacrimal gland, corneal epithelium, and conjunctival goblet cells. Vitamin D modulates tear-film stability, dampens ocular-surface inflammation, and supports goblet-cell mucin production. Deficiency associates with reduced tear film break-up time and worse Schirmer scores.
Standard evidence-based dry-eye care
- Preservative-free artificial tears — 4-6x daily.
- Warm compresses for meibomian gland dysfunction.
- Environmental modifications — humidifiers, screen breaks (20-20-20 rule).
- Omega-3 supplementation — mixed evidence but reasonable.
- Prescription cyclosporine (Restasis) or lifitegrast (Xiidra) for moderate-severe dry eye.
- Punctal plugs to reduce tear drainage.
- Vitamin D correction in the deficient — reasonable adjunct.
Practical guide
Dry-eye patients: test 25(OH)D once. Correct deficiency with 2,000 IU/day cholecalciferol. Reasonable to expect small OSDI improvement over 8-12 weeks. Continue standard artificial-tear regimen and dry-eye specialist care.