Short-term consumption of oral omega-3 and dry eye syndrome.
Purpose: To assess the effect of oral omega-3 fatty acids on tear break-up time (TBUT), Schirmer's score, and Ocular Surface Disease Index (OSDI) through a double-blind clinical trial.
Design: Randomized, double-blind clinical trial.
Participants: Sixty-four patients with dry eye symptoms between the ages of 45 and 90 years were randomized into 2 groups: 33 persons in the treatment group and 31 persons in the placebo group.
Methods: The treatment group received 2 capsules of omega-3 (each containing 180 mg eicosapentaenoic acid [EPA] and 120 mg docosahexaenoic acid [DHA]) daily for 30 days, and the placebo group received 2 medium-chain triglyceride oil capsules daily for 1 month. The outcomes were measured 1 month after the intervention.
Main outcome measures: The primary outcome measure was an increase from baseline in TBUT at day 30. Secondary outcome measures were a decrease from baseline in the OSDI score and an increase in the Schirmer's score at day 30.
Results: In the placebo group, before the intervention, the mean TBUT, OSDI, and Schirmer's scores were 4.5 ± 2.1 seconds, 36.4 ± 13.8, and 6.0 ± 2.6 mm, respectively, and 1 month later were 4.7 ± 2.6 seconds, 37.6 ± 13.5, and 6.2 ± 2.5 mm, respectively. In the treatment group, these values were 3.9 ± 1.7 seconds, 38.7 ± 16.5, and 5.8 ± 2.5 mm before the intervention and 5.67 ± 2.6 seconds, 29.3 ± 15.9, and 6.8 ± 2.8 mm after the intervention, respectively. Repeated-measures analysis of variance showed that improvements in TBUT, OSDI, and Schirmer's scores were significantly better in the treatment group than in the placebo group. The changes in the treatment and placebo groups were 71% and 3.3% for TBUT (P < 0.001), 26% and 4% (P=0.004) for dry eye symptoms, and 22.3% and 5.1% for Schirmer's score (P=0.033), respectively.
Conclusions: This study demonstrated that oral consumption of omega-3 fatty acids (180 mg EPA and 120 mg DHA twice daily for 30 days) is associated with a decrease in the rate of tear evaporation, an improvement in dry eye symptoms, and an increase in tear secretion.