ISOPT CLINICAL sponsored article asking why are we talking about omega-3 for DED treatment?
The expanding notion in disease today is that inflammation plays a role in nearly all diseases – not just rheumatoid arthritis, but artherosclerotic heart disease too. The peer-reviewed eye literature over the last decade shows increasing evidence of the role of inflammation in dry eye disease (DED)/ocular surface disease, in both animal models and people. (Wei Y, Asbell PA. The core mechanism of dry eye disease is inflammation. Eye Contact Lens 2014;40:248Y56)
Interest in omega-3 fatty acids began in the 1970s when it was observed that Inuits in the Arctic Circle had low rates of cardiovascular disease and a diet rich in omega-3. A study in the 1990s found that heart attack survivors treated with omega-3 and vitamin E were more likely to survive. As time went by, omega-3 has been advocated for heart disease, rheumatoid arthritis, asthma and many other ailments.
Essential fatty acids are fats that we, as humans, cannot produce – we need to ingest them. Omega-3 and omega-6 fatty acids, once ingested, are metabolised by the same enzymes. Omega-6 is metabolised to inflammatory mediators such as eiconosids. Omega-3 is metabolised to anti-inflammatory mediators such as EPA, DHA and resolvins. (Rosenberg ES, Asbell PA. Essential Fatty Acids in the Treatment of Dry Eye. Ocul Surf. 2010 Jan;8(1):18-28)
So what does the evidence on omega-3 show for DED? About 10 per cent of people in the USA take fish oil supplements – the third most widely used dietary supplement. However, 10 out of 12 studies found NO benefit of omega-3 for cardiovascular disease. In DED trials, the results too are mixed. Often the trials included only a small number of patients, had short treatment duration, or included only a single site and were often sponsored by a manufacturer of omega-3. The jury is still out!
The DREAM (DRy Eye Assessment and Management) Study is an NIH-sponsored, multicentre, double-blind randomised trial addressing the efficacy and safety of oral omega-3 supplements versus placebo in patients with moderate to severe DED. Five-hundred subjects will be followed over one year, including blood tests to determine compliance.
In addition to typical signs and symptoms of DED, DREAM will evaluate quality-of-life issues related to DED and cost-effectiveness of omega-3. Exploratory endpoints include contrast sensitivity, ocular surface imaging, and biomarkers on the ocular surface and in tears.
The DREAM trial will tell us if omega-3 really works in DED, will provide an in-depth profile of DED in subjects followed over a year, and explore possible new endpoints for evaluating DED. The 25 sites and the many participants look forward to sharing the expanded outlook for DED with you soon.
Prof Penny A Asbell is Professor of Ophthalmology, Director of Cornea and Refractive Services, Director of the Cornea Fellowship Programme, Department of Ophthalmology, Mount Sinai Hospital, Icahn School of Medicine at Mount Sinai, New York, USA
Penny A Asbell: firstname.lastname@example.org