Do omega-3 supplements help with dry eyes?
Recent trial raises doubts about their benefits, Christopher Labos says.
Fish oil supplements are very popular. While most people take them for their supposed cardiac benefit, there is another reason that they are sometimes recommended: dry eyes.
A surprisingly large number of people suffer from dry eyes or keratoconjunctivitis sicca. While estimates vary, it is somewhere around seven per cent of the population and is likely to rise as the population ages, because older age is a known risk factor. Women seem to be at higher risk than men, and contact lens wearers are also at higher risk. Apart from that, medications, pre-existing eye disease, eye surgery and autoimmune conditions like Sjogren’s disease can also be responsible for dry eyes.
While it might seem like a minor medical problem, dry eyes can have a significant impact on your vision, your daily activities and your daily productivity.
One economic analysis estimated that dry eyes cost the U.S. economy $55 billion annually when you consider both treatment costs and loss in productivity.
The problem is therefore not a minor one, and treatment is not always straightforward. Artificial tears are generally the first-line option. Given that dry eyes can result from inflammation that leads to decreased tear production, medicated eye drops that suppress this inflammation are also occasionally used. Another potential treatment is omega-3, or fish oil supplements.
The theory is that the anti-inflammatory action of omega-3 supplements could help with tear production.
The American Academy of Ophthalmology says that omega-3 fatty acids “may be beneficial,” but that the evidence is “insufficient to establish the effectiveness of any particular formulation.”
A recent study in the New England Journal of Medicine has also recently questioned the value of omega-3 supplements for the treatment of dry eyes. Researchers took just under 500 patients who had been suffering with moderate to severe dry eye disease for over six months and randomized them to an omega-3 supplement or a placebo pill. The omega-3 supplement was a combination of EPA and DHA, two common forms of omega-3 fatty acids.
The placebo pill was a combination of omega-9 and omega-6 fatty acids, which are not known to have any effect on eye symptoms. At one year, both groups had improved (in fact some people improved significantly), but there was no difference between the omega-3 group and the placebo group, suggesting that there was a substantial placebo effect.
It is important to note that this study is not the only one on the subject, and there are other studies showing a benefit to omega-3s for dry eye symptoms. Studies from 2013, 2016 and 2017 have shown an improvement in symptoms when omega-3s were compared to placebo.
But overall, these studies were both smaller and had a shorter followup than the current NEJM study. Followups in these studies ranged from 30 to 90 days and between 50 and 100 patients.
It is important not to throw out the baby with the bathwater, and one study in and of itself should not necessarily change standard of care, but the current study has questioned how beneficial omega-3s truly are for treating dry eyes.
People take omega-3 supplements for many reasons and I suspect many do so for their cardiovascular benefit, even though a recent meta-analysis in the Journal of the American Medical Association reviewed 10 trials comprising 78,000 individuals and found that they did not reduce fatal or non-fatal heart disease.
Whether they have any benefit for dry eyes is more in doubt now than it was before this trial was published.
The risks are likely minimal and the current study did not see any more side effects with the omega-3s compared to the placebo pill. But whether they offer any benefit given their cost remains up for debate.