Taking omega-3 fatty acids have been found to alleviate dry eye symptoms.
A study published in the journal Cornea involved giving 36 dry eye patients a 90 day regiment of fish oil containing 450 mg of eicosapentaenoic acid, 300 mg of docosahexaenoic acid and 1000 mg of flaxseed oil. The researchers were seeking to determine the effect of the supplementation on the lipid composition of meibum, aqueous tear evaporation and tear volume.
Seventy percent of those who received the fish oil supplement experienced relief of symptoms by the end of the study compared to just 7% who took the placebo. Scientists found that the supplements did not markedly alter meibum lipid composition or aqueous tear evaporation rate. Omega-3 did increased tear production and tear volume in individuals with dry eyes.
Source: Cornea. 2011;30(3):308-314.