A new, large-scale study demonstrates what optometrists have advocated anecdotally for years: A higher dietary intake of omaga-3 fatty acids decreases the incidence of dry eye in women, according to an article in Octobers American Journal of Clinical Nutrition.

This study, part of Brigham and Womens Hospitals Womens Health Study, included 32,470 women aged 45 to 84 years. Researchers assessed fatty acid intake with a food-frequency questionnaire and assessed dry eye syndrome with self-reports of clinically diagnosed cases. Of the sample, 4.7% reported dry eye syndrome.

Women with the highest levels of omega-3 in their diets had a 20% reduced risk of dry eye compared with women with the lowest levels of omega-3 in their diet.

Women who ate at least five servings of tuna per week had a 68% reduced risk of dry eye compared with women who ate one serving per week.

Eating fish that have lower levels of omega-3 fatty acids than tuna did not appear to protect against dry eye syndrome.

A high intake of omega-6, a fat found in many cooking and salad oils and animal meats, may increase the risk of dry eye syndrome.

Based on this report, preventing dry eye syndrome is another potential reason to follow a diet rich in tuna and other foods plentiful in omega-3 fatty acids, says optometrist Debra Schaumberg, Sc.D., M.P.H., the senior author of the study.

Miljanovic B, Trivedi KA, Dana MR, et al. Relation between dietary n-3 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women. Am J Clin Nutr 2005 Oct;82(4): 887-93.