SEP 01, 2022
Comprehensive Ophthalmology, Cornea/External Disease
While previous research has examined the efficacy of omega-3 supplements to treat dry eye disease (DED), this study focused on the supplement’s potential for preventing the onset of DED.
This was a prespecified ancillary study of the Vitamin D and Omega-3 Trial (VITAL). The VITAL trial is a nationwide, randomized, double-blind, placebo-controlled trial evaluating whether the use of vitamin D or marine omega-3 fatty acids reduces the risk of cancer and cardiovascular disease. Participants included women 55 years or older and men 50 years or older, and for this ancillary study, participants also were free of dry eye disease or severe dry eye symptoms. Individuals in the VITAL study were assigned to either: 1) fish oil and vitamin D, 2) fish oil and placebo vitamin D, 3) placebo fish oil and vitamin D, or 4) placebo fish oil and placebo vitamin D. In the ancillary study, analysis was performed comparing the omega-3 and placebo omega-3 groups, adjusting for vitamin D assignment. The primary end point was a new diagnosis of dry eye disease (confirmed by records review or a clinician questionnaire) and the secondary end point was a composite of new dry eye disease diagnoses and all patient reports of severe dry eye symptoms (obtained by questionnaire).
The median follow-up in this study was 5.3 years. Patients assigned to the placebo group and patients assigned to the omega-3 group demonstrated similar rates of new diagnoses of dry eye disease and new onset of severe dry eye symptoms. Exclusions of end points confirmed early in the follow-up period did not change this finding.
A limitation of the study is that dry eye was diagnosed not by studying ophthalmology exams, but by patient report followed by records review. This approach may underestimate the number of patients with new dry eye diagnoses. Subtypes of dry eye disease also were not differentiated in this study. Additionally, the dose of 1 g per day of marine omega-3 fatty acids may not have been high enough to see an effect.
This randomized clinical trial demonstrated that long-term supplementation with marine omega-3 fatty acids does not decrease the incidence of dry eye diagnosis or severe dry eye symptoms. This study, therefore, does not support use of omega-3 fatty acids to prevent dry eye disease.