Ricki Lewis, PhD
April 13, 2018
Omega-3 fatty acid supplements do not alleviate dry eye disease, according to results from a randomized controlled trial.
Maureen G. Maguire, PhD, Carolyn F. Jones Professor of Ophthalmology at the University of Pennsylvania Perelman School of Medicine in Philadelphia, and the Dry Eye Assessment and Management Study (DREAM) Research Group reported the findings today at the Annual Meeting of the American Society of Cataract and Refractive Surgery (ASCRS) in Washington, DC, and publishedthem in the New England Journal of Medicine.
Many eye care clinicians recommend omega-3 dietary supplements to relieve dry eyes because the fatty acids have anti-inflammatory properties and are safe to use. However, the American Academy of Ophthalmology Preferred Practice Pattern guidelines state that “the evidence is insufficient to establish the effectiveness” of omega-3 fatty acid supplementation in combating dry eyes.
To investigate the efficacy of fatty acid supplementation, Maguire and colleagues conducted a multicenter, double-blind clinical trial in which they randomly assigned patients with moderate to severe dry eye disease to receive daily either 3000 mg fish oil (containing omega-3 eicosapentaenoic and docosahexaenoic acids) or olive oil placebo. The patients had to have demonstrated dry eye on two consecutive exams 2 weeks apart before enrollment.
Each participant took 5 capsules a day. The experimental group capsules each contained 400 mg eicosapentaenoic acid and 200 mg docosahexaenoic acid, and each placebo capsule contained 68% oleic acid, 13% palmitic acid, and 11% linoleic acid. All capsules also contained vitamin E.
Participants represented the “real world” of dry eyes because they were recruited from private and academic eye care practices throughout the United States and continued whatever treatments they had been using throughout the study. They reported having had symptoms for at least 6 months, having used artificial tears at least twice daily for the 2 weeks before the screening visit, and scored between 25 and 80 on the Ocular Surface Disease Index at the initial screen and 21 and 80 at the eligibility confirmation visit.
Patients also had to have at least two of four signs in at least one eye: a conjunctival lissamine-green staining score of 1 or more, a corneal fluorescein staining score of 4 or more, tear break-up time of 7 seconds or less, and a Schirmer’s test result (the length of paper strips placed in the lower eyelid that remain wet) of 1 to 7 mm in 5 minutes.
The trial enrolled 329 patients in the fatty acids group and 170 in the placebo group.
There was no significant difference between the groups in mean Ocular Surface Disease Index change from baseline to 12 months, which was the primary endpoint. Specifically, the mean change in the supplement group was −13.9 points vs −12.5 points in the control group, with mean difference in change after accounting for missing data of −1.9 points (95% confidence interval [CI], −5.0 to 1.1; P = .21).
The authors also saw no significant differences in secondary endpoints, including conjunctival staining score (mean difference in change, 0.0 points; 95% CI, −0.2 to 0.1 point), corneal staining score (0.1 point; 95% CI, −0.2 to 0.4 point), tear break-up time (0.2 seconds; 95% CI, −0.1 to 0.5 seconds), or Schirmer’s test (0.0 mm; 95% CI, −0.8 to 0.9 mm).
By 12 months, the level of omega-3 fatty acids in red blood cell membranes indicated that 85.2% of the participants in the supplement group had adhered to the treatment.
Symptoms and signs of dry eye disease improved to the same degree for patients who received omega-3 fatty acid supplements and for those who received the olive oil placebo. “There was virtually no difference between the two groups in the improvement in four key signs of dry eye disease,” the researchers conclude.
The observation that the differences in secondary outcomes between the active supplement group and the participants receiving olive oil were small and not significant suggests a “substantial” placebo effect, the investigators write.
The new study included more participants than did past investigations. The researchers hypothesize that the DREAM trial did not confirm efficacy of omega-3 fatty acids in dry eye disease shown in some smaller trials because of the expanded eligibility criteria. Subgroup analyses that mimicked requirements of other trials, such as requiring osmolarity measures and evidence of meibomian gland dysfunction, also did not indicate benefit of omega-3 supplementation beyond that of placebo.
Several coauthors report receiving grants, personal fees, or nonfinancial support from one or more of the following companies: Santen, Shire, Medscape, Allergan, ScientiaCME, Oculus, Kao, Novartis, MC2 Therapeutics, Valeant, Bausch& Lomb, Rtech, Miotech, Alcon, Johnson & Johnson VIsion Care, Chengdu Kanghong Biotech Co Ltd, and Ziemer Ophthalmic Systems AG. The other authors have disclosed no relevant financial relationships.
N Engl J Med. Published online April 13, 2018. Article
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