Omega-3 fatty acid supplements appear no better than placebo at relieving symptoms and signs of dry eye disease, according to new research. The multicenter study, funded by NIH's National Eye Institute, involved 535 patients with moderate-to-severe dry eye disease. Participants were randomly assigned to receive a daily oral dose of 3,000 mg of fish-derived omega-3 fatty acid capsules or an olive oil placebo capsule. Each active capsule contained 400 mg of EPA and 200 mg of DHA, for a total daily dose of 2,000 mg of EPA and 1000 mg of DHA, while each placebo capsule contained 1,000 mg of refined olive oil. Patients who were regularly using treatments for dry eye disease, systemic medications that are known to cause ocular dryness, systemic glucocorticoids, or other immunosuppressive agents were allowed to continue those medications. The data showed that the mean change in the Ocular Surface Disease Index score was not significantly different between the two groups, including across prespecified subgroups. In addition, there were no significant changes between the two groups in mean changes from baseline in the conjunctival staining score, corneal staining score, tear break-up time, and result on Schirmer's test. Rates of adverse events were similar in the two groups. "We found no evidence of a beneficial effect of n-3 fatty acid supplements as compared with placebo supplements among patients with dry eye disease," the researchers concluded.