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Open WellbeingWhat the studies actually measured

Long-term health and immunity

Omega-3 fatty acids (EPA/DHA)and Dry eye symptom severity

Only one source here so far, and it found no clear difference in dry eye symptom severity.

How sure anyone can be

Low certainty, level 2 of 4

Further research is likely to change this.

The numbers reported

One source’s range, drawn against its own line of no difference and scaled to its own numbers.

-5.14-2.470.19

This range crosses the no-difference line, so these numbers fit a real difference and no difference at all equally well.

Bar the confidence interval — the range the true effect is likely to sit inNotch the number the source reportedLine where there would be no difference at all

One source, newest first

What we read is the published abstract, not the full paper, so a blank below may still be printed in the paper itself. A fixed rule worked this out from the source’s own fields. Nobody checked this rating by hand.

  • Systematic review, 2019 · 4 studies pooled · 677 participants

    Low certainty, level 2 of 4

    Omega-3 and omega-6 polyunsaturated fatty acids for dry eye disease.

    Cochrane Database Syst Rev. 2019;12(12):CD011016. doi:10.1002/14651858.CD011016.pub2. PMID:31847055.

    This source later carried a notice: Update of doi: 10.1002/14651858.CD011016. The number below is exactly as the source gave it.

    Number reported
    -2.47
    Which way it went
    No clear difference
    Likely range
    -5.14 to 0.19
    Source’s own words
    mean difference in dry eye symptom score units vs placebo
    Who was studied
    Adult with dry eye disease
    Compared with
    placebo or no treatment
    Amount taken
    Not in the abstract
    For how long
    30 to 365 days
    Disagreement between studies
    Not in the abstract
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 2 steps down: risk of bias and imprecision
    1. Starts at High
    2. Risk of bias brought it down to Moderatethe abstract's own appraisal reports serious study limitationsReported in the abstract
    3. Imprecision brought it down to Lowthe confidence interval includes no effectReported in the abstract
    4. Ends at Low2 steps down.
    Checked, nothing to step it down for
    indirectness
    Inconsistency
    No high disagreement reported between the 4 studies it pooled

    Imprecision stops at the first check that applies; others may apply too.

    AI review could not confirm it — an AI agent re-read this finding against the saved source and at least one check failed. The batch record names the check and quotes the sentence that caused the doubt. No person read it.

    Read the abstract on PubMed

What is still missing from these readings

  • Amount taken — Not in the abstract.

Something nobody wrote down is never a zero and never a guess.

Still to read for Omega-3 fatty acids (EPA/DHA)

Seven of the 19 things on our list for Omega-3 fatty acids (EPA/DHA) have no reading here yet:

  • Alanine aminotransferase (ALT)
  • Cognitive performance
  • Gestational length
  • HDL cholesterol
  • Heart rate variability (RMSSD)
  • High-sensitivity CRP
  • Resting heart rate

Still to read means nobody here has got to it, not that it was tried and did nothing or that no research exists. A pairing on no list is not a gap: we never set out to read it.

Read next

This is a library, not advice. No recommendation, no dose, no diagnosis, no ranking. We never ask about your symptoms, and nothing here is tailored to you.