n-3 Fatty Acid Supplementation for the Treatment of Dry Eye Disease.

I think the authors are missing the point in this new england journal of medicine article, don't stop using your fish oil....

N Engl J Med. 2018 Apr 13.

n-3 Fatty Acid Supplementation for the Treatment of Dry Eye Disease.

Dry eye disease is a chronic condition that is characterized by inadequate lubrication of the eye surface by tears. Supplements of n−3 fatty acids (often called omega-3 fatty acids) are used to relieve symptoms.

A multicenter, double-blind clinical trial, assigned patients with moderate-to-severe dry eye disease to receive a daily oral dose of 3000 mg of fish-derived n-3 eicosapentaenoic and docosahexaenoic acids (active supplement group) or an olive oil placebo (placebo group). They did not observe better outcomes in omega-3 fatty acids group compared to placebo

Wrong use of Olive oil as placebo

Olive oil is composed mainly of the mixed triglyceride esters of oleic acid and palmitic acid and of other fatty acids, along with traces of squalene. They have therapeutic effect on dry eye, use something that can serve as a real control with no therapeutic benefits.

Biased conclusion:

Conclusions Among patients with dry eye disease, those who were randomly assigned to receive supplements containing 3000 mg of n-3 fatty acids for 12 months did not have significantly better outcomes than those who were assigned to receive placebo.

Correct conclusion:

OSDI (Figure 1. Distribution of Scores on the Ocular Surface Disease Index.)scores decreased between baseline and 12 months in the active supplement group and in the placebo group (P<0.001 for change in each group); most of the decrease was during the first 3 months (Figure 1). The mean (±SD) change in the total OSDI score was −13.9±15.6 points in the active supplement group and −12.5±18.2 points in the placebo group

Figure from the article