Study design

Patients who were in the omega-3 fatty acid supplement group and completed 12-months of follow up in the DREAM study were eligible for this extension study. Participants were randomly assigned in a 1:1 ratio to continue supplementation (3,000 mg; n=22) or to take placebo (refined olive oil; n=21) for an additional 12 months. The primary outcome was change in Ocular Surface Disease Index (OSDI) score from 12 months to 24 months. Secondary outcomes included lissamine staining, fluorescein staining, corneal staining, TBUT and Schirmer test with anesthetic.

Outcomes

At 12 months, investigators found no statistically significant difference in changes in symptoms or signs of dry eye disease between groups. The mean values of the percentage of EPA and DHA in red blood cells decreased in the placebo group, indicating the active supplement group was taking the supplement and the placebo group was not.

Limitations

Recruitment for this extension trial was limited as the DREAM trial required more time and resources than the study anticipated. Although the controlled withdrawal design of this extension trial was novel, it was limited by a small sample size. The original DREAM study recruited patients with a very broad dry eye disease inclusion criteria—it is possible that smaller defined subsets of patient responses to the supplement are not well represented.

Clinical significance

The results from this DREAM extension trial are consistent with the results of the primary DREAM clinical trial and do not support a measurable significant beneficial effect of oral omega-3 fatty acid supplementation for the treatment of dry eye disease as defined in this paper.