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    Ingredient guide · Ingredient reference

    Can vitamin D deficiency affect your eyes? Dry-eye evidence and limits

    Low vitamin D has been associated with dry eye, and some supplementation studies report improvements. The evidence is not strong enough to explain every eye symptom or establish a universal treatment dose. New vision changes still need eye assessment; vitamin D is not a substitute for determining the cause.

    Read the evidence ↓

    Supplement Science Insights Editorial Team

    Published September 23, 2026

    Dry eye is the main question in this evidence

    A 2024 meta-analysis reported improvements in several tear and symptom measures after vitamin D supplementation. It included eight studies and described a possible adjunctive role. Its before-and-after comparisons do not carry the same causal strength as a well-controlled treatment trial. [1]

    A later review highlights the evidence gaps

    A 2026 systematic review of oral vitamins for dry eye found that none of its thirteen included studies was high quality. Problems included inadequate controls or power, short follow-up and varied dosing. Vitamin D was frequently studied, but the review did not establish a dependable general treatment regimen. [2]

    Do not confuse vitamin D with vitamin A deficiency

    NIH describes vitamin A deficiency as a cause of night blindness and severe eye-surface disease. That is a different nutrient and clinical problem from a low vitamin D result. An unexplained vision symptom cannot identify which vitamin, if any, is deficient. [3][4]

    Assess the symptom and treat any deficiency appropriately

    Dry-eye symptoms can need local eye care and assessment of contributing factors. A vitamin D deficiency can be addressed alongside that care without promising it will resolve every symptom. NHS advises urgent assessment for concerning combinations such as painful red eyes, marked light sensitivity or vision changes. [5][4]

    Avoid a supplement-only diagnosis

    Imagine a person has both a low vitamin D result and new blurred vision. Their coexistence does not prove that D replacement will fix the vision. Arrange appropriate eye assessment and use nutritional treatment for the documented need rather than waiting for an uncertain response. [5][2]

    Hypothetical example — interpret vitamin D and eye findings
    FindingEvidence boundary
    Low D with dry eyeAssociation does not establish sole cause
    Symptoms improved before versus afterOther explanations may remain
    Variable small studiesNo universal eye-treatment dose
    New concerning vision changeRequires eye assessment
    Can vitamin D deficiency affect your eyes? Dry-eye evidence and limits — original article outline diagram
    Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

    Sources for this article

    1. The efficacy of vitamin D supplementation in dry eye disease: A systematic review and meta-analysis.
      Source consulted: 2026-09-21. This is a reference resource, not a claim that we conducted the studies or tested a product.
    2. The Efficacy of Oral Vitamin Supplementation in Dry Eye Disease: A Systematic Review - PMC
      Source consulted: 2026-09-21. This is a reference resource, not a claim that we conducted the studies or tested a product.
    3. Vitamin A and Carotenoids - Health Professional Fact Sheet
      Source consulted: 2026-09-21. This is a reference resource, not a claim that we conducted the studies or tested a product.
    4. Vitamin D - Health Professional Fact Sheet
      Source consulted: 2026-09-21. This is a reference resource, not a claim that we conducted the studies or tested a product.
    5. NHS: Dry eyes
      Source consulted: 2026-09-21. This is a reference resource, not a claim that we conducted the studies or tested a product.