Study confirms that nutrition plays a role in dry eye disease
Various news outlets recently reported that omega-3 supplementation is ineffective against dry eye disease (DED), based on a New England Journal of Medicine study, conducted by the Dry Eye Assessment and Management (DREAM) Study Research Group. (See https://bit.ly/2HobZo1 .)
Here, I provide a brief overview of the study, why I think the news outlets misinterpreted its results, what I feel is the study’s limitation and what additional research shows.
In the multicenter, double-blind clinical trial, moderate to severe DED patients were randomly assigned to receive either 3,000 mg of omega-3 fatty acids (2,000 mg EPA/1,000 mg DHA) (329 patients) or placebo, which was olive oil (68% oleic acid, 13% palmitic acid, 11% linoleic acid) (170 patients).
Patients needed to be taking artificial tears twice daily for at least two weeks before the screening visit and were allowed to have been taking up to 1,200 mg of omega-3 fatty acids daily prior to entering the study.
All participants were advised to continue using their current DED treatments, such as artificial tears, prescription drops, warm compresses and lid scrubs.
The researchers reviewed the patients’ DED conditions at six months and 12 months. The omega-3 group had an ocular surface disease index (OSDI) improvement of 13.9 points compared to a 12.5 point improvement in the placebo group. Also, the researchers saw no significant differences in conjunctival staining, corneal staining, TBUT and Schirmer’s test results. The conclusion: Omega-3 supplementation didn’t provide significantly better outcomes than olive oil.
I would argue that the study’s conclusion is not tantamount to saying omega-3 supplementation is ineffective against DED.
The placebo was olive oil. So, what the study’s result actually shows is that taking olive oil every day can also improve DED symptoms and signs.
Remember: The study shows OSDI improvements from both omega-3 supplementation and olive oil. Given this, it seems the DREAM study compares two treatments. In fact, the study’s researchers said they were surprised by the efficacy of olive oil in reducing the signs and symptoms of DED.
The DREAM study was not a study on omega-3 supplementation and olive oil alone, as subjects were permitted to and remained on other DED treatments. As a result, true efficacy of either couldn’t be measured.
In May’s Cornea, a meta-analysis of 17 randomized controlled trials comprised of 3,363 DED patients shows omega-3 supplementation “significantly” improves DED signs and symptoms when compared with placebo, indicating that: “Omega-3 supplementation may be an effective treatment for dry eye disease.”
The DREAM results actually confirm that nutrition is a factor in DED management. Thus, O.D.s should counsel patients on the importance of increasing the intake of salmon, rainbow trout, sardines and mackerel, that contain healthy fats, and to use olive oil for food preparation. Should diet alone not be enough, O.D.s should consider supplementing with omega-3 fatty acids or a supplement that contains omega-3 fatty acids and GLA (an omega-6 fatty acid), as research clearly shows they have an important role in the management of this chronic condition. OM