There is no evidence for the benefit of omega-3 acid supplementation in treating symptoms of dry eye disease, a study has shown
Omega-3 fatty acid supplements are often recommended for people with dry eye disease. However, there is no conclusive evidence that they are effective in resolving symptoms.
Researchers carried out a randomised trial involving 349 patients with moderate-to-severe dry eye disease who were assigned to daily 3,000mg omega-3 acid supplementation, compared with 186 patients assigned to olive oil placebo (equivalent to one teaspoon per day).
After 12 months, the researchers found no significant difference between the two groups regarding dry eye disease symptom severity. There was also no difference in secondary outcomes, including corneal damage and tear production.
“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 authors said in the New England Journal of Medicine (3 May 2018).
 Dry Eye Assessment and Management Study Research Group. n-3 Fatty Acid Supplementation for the Treatment of Dry Eye Disease. N Engl J Med 2018;378:1681–1690. doi: 10.1056/NEJMoa1709691