Fish oil supplements have always been recommended to people suffering from dry eye disease, a common ailment that affects millions worldwide - but a study out Friday says they don't work.
Out of those people, 349 were randomly selected to receive 3 grams of fish-derived omega-3 fatty acids per day, in five capsules.
Dry eye disease affects more than 16 million Americans, causing burning, itching, stinging, and impaired vision.
Those randomized to daily doses of 3,000 mg of eicosapentaenoic and docosahexaenoic acids in the so-called DREAM study showed a mean 13.9-point decline in Ocular Surface Disease Index (OSDI) score after 12 months, compared to a 12.5-point decline among patients receiving an olive oil placebo (P=0.21), reported Maureen G. Maguire, PhD, of the University of Pennsylvania in Philadelphia, and colleagues.
Many dry eye sufferers take fish oil supplements even though research demonstrating the pills' effectiveness for the condition have been lacking, Maguire's group said. Members of both groups were free to keep using other dry eye remedies, such as artificial tears and prescription anti-inflammatory eye drops.
The findings were presented at the American Society of Cataract and Refractive Surgery meeting Friday and published simultaneously in the New England Journal of Medicine. The study was "double-blinded", meaning neither the researchers nor the participants knew if they were given the supplement or the placebo. "This well-controlled investigation conducted by the independently-led Dry Eye Assessment and Management (DREAM) Research Group shows that omega-3 supplements are no better than placebo for typical patients who suffer from dry eye".
There were no clinically significant treatment differences between the active and placebo groups for OSDI scores, Brief Ocular Discomfort Index scores, SF-36 scores, four key signs of dry eye disease, dry eye disease treatment, and serious or nonserious adverse events, Asbell said.
A total of 61 percent of people in the omega-3 group and 54 percent of those in the control group achieved at least a 10-point improved, but the difference between groups was not statistically significant.
According to Matthew Gorski, an ophthalmologist at Northwell Health in NY, doctors interested in dry eye and the effectiveness of fish oil supplements have "eagerly awaited results of clinical trials with the hope that it would potentially improve one's quality of life".
The U.S. National Center for Complementary and Integrative Health has more about omega-3 supplements.