About 14 percent of U.S. adults have dry eye, which causes pain and vision problems. It’s more common in women and with age, and is related to inflammation.

Omega-3 fatty acids in fish oil may reduce inflammation, so doctors thought they might help more than the artificial tears, eyedrops and other treatments patients use now.

A federally funded study gave 500 people daily doses of fish oil or dummy capsules. After one year, dry eye symptoms were similar in both groups.

Results were discussed at a conference in April in Washington and published by the New England Journal of Medicine.