At a 2018 ophthalmology meeting, an instant poll asked the audience whether omega-3 supplements help dry eye. Ninety percent said yes, at least for some patients.
A large trial published that same year suggested the other ten percent had it right. The way that trial was designed — and argued about afterwards — is more instructive than the headline result.
Why the idea made sense
Dry eye disease is not simply a lubrication problem. Inflammation is described as its core mechanism[6], and that framing is what brought omega-3 into the conversation.
EPA and DHA are precursors to signalling molecules involved in resolving inflammation. If inflammation drives the condition, a dietary intervention that shifts inflammatory signalling might help.
The idea was plausible enough that it became standard advice. Hence the ninety percent.
What DREAM did
The Dry Eye Assessment and Management study was funded by the US National Institutes of Health and published in the *New England Journal of Medicine* in 2018.
The design was substantial[4]:
- 535 participants with at least six months of moderate-to-severe dry eye disease
- 27 clinical centres across the United States
- Randomised 2:1 to omega-3 or placebo
- Active dose: 3,000 mg daily — 2,000 mg EPA plus 1,000 mg DHA in triglyceride form
- Placebo: 5,000 mg refined olive oil
- Five soft gelatin capsules daily, identical in size, colour and aroma[3]
- Twelve months, double-masked
Mean age was 58, and participants were predominantly female[2]. Eligibility required signs of dry eye by at least two of four objective measures — conjunctival staining, corneal staining, tear break-up time, or Schirmer testing[2].
Participants were permitted to continue existing dry eye treatments, including artificial tears and prescription anti-inflammatory drops[2]. The study chair described this as deliberate: omega-3 is generally used as add-on therapy, and the trial aimed to reflect that real-world context[2].
What it found
The primary outcome was change in the Ocular Surface Disease Index, a validated symptom score.
Both groups improved substantially. OSDI dropped a mean of 13.9 points in the omega-3 group and 12.5 points in the placebo group[2].
The difference between them was not statistically significant[2]. Nor were differences in any secondary outcome — conjunctival staining, corneal staining, tear break-up time, or Schirmer testing[2]. Adverse event rates were similar[2].
Here’s the part I keep returning to. A 12.5-point improvement in the placebo group is not a small number. Read in isolation, an improvement of that size would look like strong evidence a treatment works. The comparison group nearly matched the treatment group — and without a comparison group, nobody would have known.
Symptoms in this condition improve considerably under trial conditions regardless of what’s in the capsule.
The extension: stopping made no difference either
A follow-up study tested the reverse question.
Participants who had taken omega-3 for the full twelve months were re-randomised — half continued, half switched to olive oil placebo — for another twelve months[5].
Among 22 continuing and 21 switched, the change in OSDI between month 12 and month 24 was −0.6 points, 95% CI (−10.7, 9.5), p = 0.91[5]. No significant differences in conjunctival staining, corneal staining, tear break-up time or Schirmer testing either[5].
Two caveats. The sample was small — enrolment fell short of target[3]. And a wide confidence interval like that one can’t rule out a modest effect.
Still, the direction is consistent. Starting it didn’t produce a measurable benefit, and stopping it didn’t produce a measurable loss.
The objections, which are worth taking seriously
DREAM was criticised, and not unreasonably.
The placebo wasn’t inert. Olive oil is a fat with its own biological activity. Comparing a supplement against a substance that may itself do something is a different test from comparing against nothing.
Concurrent treatment muddied the picture. One critic noted that allowing participants to remain on existing dry eye therapies “adds a lot of co-variables”[1]. It also plausibly contributed to the large improvement seen in both arms.
A near-miss on responder analysis. 61% of the treatment group and 54% of the control group achieved a 10-point OSDI improvement — a difference that did not reach statistical significance[7].
These are legitimate points. They don’t establish that omega-3 works; they establish that DREAM tested a specific question — omega-3 added on top of ongoing care, against an olive oil comparator — and answered that one.
A bit more detail — on why funding disclosure matters here. Trials reporting positive results in this area exist. One reported significant reductions in tear osmolarity, improvements in tear break-up time and omega-3 index, and reduced OSDI and MMP-9 positivity. That study was funded by a nutraceutical company[3]. Industry funding doesn’t make results wrong, and DREAM’s NIH funding doesn’t make it right. But when trials disagree, knowing who paid for each is part of reading them.
If you’re in Korea
One regulatory point clarifies things considerably.
Omega-3’s approved functional claims in Korea relate to blood triglycerides and circulation — not to dry eye. Whatever a product’s marketing suggests, dry eye is not among the functions it was authorised for here.
That’s a useful test to apply generally. If a product is being recommended to you for a purpose outside its approved claim, the recommendation is coming from somewhere other than the regulatory review. The recognised wording for any ingredient can be checked on the official food safety portal[8].
Two practical additions for readers here. Dry eye is common in Korea, and screen-heavy work and dry winter air both contribute. And if symptoms persist, an ophthalmologist can distinguish between the underlying types of dry eye — which matters, because they respond to different treatments. That’s a more productive route than trialling supplements.
Closing
The lasting lesson from DREAM isn’t that omega-3 failed. It’s what the placebo arm revealed.
A 12.5-point symptom improvement, in people taking olive oil capsules. Had that group not existed, the 13.9-point improvement in the treatment arm would have looked like a clear success — and it would have been reported that way.
That’s the whole argument for controlled trials in one comparison. It also explains why testimonials in this category are so consistently positive, and so consistently unpersuasive. People genuinely do improve. Establishing what caused the improvement is a separate problem entirely.
At a Glance
- Dry eye’s core mechanism is described as inflammation, which is what made omega-3 plausible
- DREAM: 535 participants, 27 centres, 3,000 mg omega-3 (2,000 EPA + 1,000 DHA) vs 5,000 mg olive oil, 12 months
- OSDI improved 9 points on omega-3 and 12.5 points on placebo — not a significant difference
- No significant differences in staining, tear break-up time, or Schirmer testing
- Extension study: stopping omega-3 after 12 months also produced no measurable change (p = 0.91)
- Objections: olive oil is not an inert placebo, and participants continued existing treatments
- A contrasting positive trial in this area was funded by a nutraceutical company
- In Korea, omega-3’s approved claims cover blood triglycerides and circulation — not dry eye
※ This article is for general information and does not replace medical advice, diagnosis or treatment. Persistent eye discomfort, redness, pain or vision change warrants examination by an ophthalmologist rather than self-treatment. Omega-3 supplements can affect bleeding and interact with anticoagulant medication — consult a clinician if you take any prescribed medicine.
References
- “DREAM study reflects ‘real-world’ dry eye disease patients”, Healio (trial design, dosing, and criticism of concurrent therapy), https://www.healio.com/news/ophthalmology/20180814/dream-study-reflects-realworld-dry-eye-disease-patients
- “DREAM study: Omega-3 no better than olive oil for dry eye”, Healio (primary and secondary outcomes, baseline characteristics), https://www.healio.com/news/optometry/20180416/dream-study-omega3-no-better-than-olive-oil-for-dry-eye
- “DREAM Interpretations Abound Following Surprising Dry Eye Study Findings”, CRSToday (capsule masking, contrasting industry-funded trial), https://crstoday.com/articles/june-2018/dream-interpretations-abound-following-surprising-dry-eye-study-findings
- “DRy Eye Evaluation And Management (DREAM)”, Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania, https://www.med.upenn.edu/cpob/dream/
- “The Dry Eye Assessment and Management (DREAM) extension study — A randomized clinical trial of withdrawal of supplementation with omega-3 fatty acid in patients with dry eye disease”, PubMed, https://pubmed.ncbi.nlm.nih.gov/31425752/
- Wei Y, Asbell PA. “The core mechanism of dry eye disease is inflammation”, Eye & Contact Lens 2014;40:248-56 (cited within the DREAM extension study reference list), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4104780/
- “Dry Eye: Where Do We Stand with Omega-3 Supplements?”, Review of Optometry (responder analysis figures), https://www.reviewofoptometry.com/article/dry-eye-where-do-we-stand-with-omega3-supplements
- Food Safety Korea (MFDS), recognised functional ingredient and approved wording lookup, https://www.foodsafetykorea.go.kr/