Omega-3s For Dry Eye Disease? Not the Answer According to This Study

Hopes that taking omega-3 supplements would be an easy and inexpensive way to treat drug eye disease were dealt a setback this week when Korean investigators reported negative results from a randomized clinical trial in the JAMA Ophthalmology.

It was relatively small study involving 132 patients, and the results on some secondary outcomes suggest a possible benefit. But this result comes after negative results from the larger DREAM clinical trial that were reported in the New England Journal of Medicine in 2018 and an 2019 Cochrane review that was, at best, equivocal.

In an invited commentary on the Korean results, Ian J. Saldana, M.B.B.S., M.P.H., Ph.D., of Johns Hopkins Bloomberg School of Public Health, left the door slightly ajar on omega-3 supplements for dry eye disease. “More work may need to be done before the field makes a firm conclusion and fully closes the chapter on omega-3 fatty acid supplements for patients with evaporative dry eye,” he wrote.

Some studies have suggested that omega-3 supplements could help with dry eye disease, and it is biologically plausible that they might. The teary film that coats the front of the eye has an outer layer rich in fats, called the meibum, that helps keep the watery underlayer from evaporating too quickly. Most dry eye disease is caused dysfunctional meibomian glands that don’t produce enough meibum or a version of it that isn’t stable. The thinking is that oral omega-3 supplements could help restore the mebium and reduce the evaporation that results in dry eyes. Research produced enough positive results to merit randomized clinical trials.

Corresponding author Joon Young Hyon, M.D., Ph.D., of Seoul National University’s Bundang Hospital and his colleagues, and colleagues enrolled 132 patients with dry eye disease into the study. Some patients were lost to follow up, so the researchers ended up with 58 participants in the omega-3 group and 57 in the control group. The people in the omega-3 group took four capsules daily that contained 1680 milligrams (mg) of eicosapentaenoic acid and 560 mg of docosahexaenoic acid. The people in the control group took four capsules a day containing 3,000 mg of grape-seed oil. The main endpoint was the Ocular Surface Disease Index (OSDI) at the beginning of the study compared with what it was six weeks and 12 weeks. OSDI is 12-item questionnaire developed by Allergan that provides an assessment of dry eye disease and its effects on vision. The index generates scores from 1-100 with higher scores indicating a worse case of dry eye disease and scores 33 and greater rated as severe dry eye disease.

At 12 weeks, both the omeg-3 group and the grape-seed oil group experienced, on average, fairly large improvements in their OSDI scores compared with their baseline scores, which was 43.5, on average, for the omega-3 group and 44.1for the grape-seed group. The omega-3 group improved by 22.7 points and the grape-seed oil group by 18.8. According to Hyon and colleagues, previous research has shown that OSDI score changes of 7.3 to 13.4 result in meaningful clinical differences for patients with severe dry eye disease, so that threshold was met in this study. But results shows that difference in the change in OSDI between omega-3 group and the grape-seed oil group was smaller than a difference that would translated into a clinically significant difference. At 12 weeks, the difference in OSDI improvement between the two groups was 3.9 (22.7 for the omega-3 group and 18.8 for the grape-seed oil group).

Hyon and the co-authors note that grape-seed oil, through its antioxidant properties, may be good for eye health in general.

There were some differences between the two groups on some of the secondary outcomes, and Hyon said results of the TBUT (tear break up time) test, which assesses the stability of the tear are suggestive of a clinical difference. But they cautioned that this was, in fact, a secondary outcome and should be used for “hypothesis generation.”