Omega-3 (2005, 2016) and Dry Eyes
Learn more about dry eyes support
Researchers know that omega-3 fatty acids are valuable in vision health, and that previous research has demonstrated that high intakes of omega-3s taken in foods (like fish) contribute as much as 66% reduction in dry eye syndrome in a large sample of women who ate 5-6 servings of tuna weekly.1
Researchers wanted to know whether a particular formulation of omega-3s were effective for dry eyes - a condition apparently only indirectly related to the health of the retina and nervous system functions.
In a placebo-controlled, double-blind study about 100 participants randomly received re-esterized omega-3s or placebo. The distinction is interesting. There is much concern because fish rich in omega-3s may also have high levels of contaminants such as mercury unless properly processed by the manufacturer. Most fish oils add ethyl alcohol to detoxify at least some contaminants.
The definitions get confusing: Re-esterized fish oil is derived from crude fish oil which is altered with ethanol and then distilled under heat to remove contamination. It results in concentrated omega-3 molecules in an ethyl ester "package" which has been criticized as less stable.2
This study involving 're-esterized' fish oil included a process to remove the alcohol and create a more natural form of omega-3 which is both better tolerated by the body when taken orally and which is more readily absorbed.
The indicators of dry eye syndrome in the patients were measured at the beginning of the study, at the 6th week, and at the 12th week. Standard tests for dry eye were used including the tear osmolarity, the Schirmer test, corneal staining and others.
The participants were asked to continue their normal diets and that they should continue their normal usage and brand of artificial tears. Right before they came for each testing session they were asked to discontinue use of contacts and artificial tears.
- The primary concern was tear osmolarity, that is, the saltiness of tear fluid. Osmolarity in the omega-3 group decreased significantly compared to the control group.
- Omega-3 index scores (the % of DHA and EPA in red blood cells) also improved significantly in the omega-3 group compared to the control group.
- Tear break up time (TBUT) refers to how fast the tear film protecting the surface of the cornea begins to break up. Normally, each time you blink the tear film is redistributed across the eye. If it breaks up quickly then you have to blink a lot to maintain the even distribution. This measurement also displayed a signifiant improvement.
- Levels of inflammation are measured by an MMP-9 test (matrix metalloproteinase-9). Again, the omega-3 group shows significant improvement.
- The ocular disease surface index (OSDI) scores the overall severity level of chronic dry eye. This score improved for the omega-3 group.
- Corneal staining, Schirmer score, MGD stage - for these tests there were improvements but they were not as significant.
Of particular interest was that many of the signs and symptoms of chronic dry eye improved relatively quickly, as early as 6 weeks.
Researchers: Alice T. Epitropoulous, MD, Eric D. Donnenfeld, MD, et al
Published: Effect of Oral Re-esterified Omega-3 Nutritional Supplementation on Dry Eyes, Cornia, September, 2016.
Researchers found that women with a higher dietary omega-3 fatty acid consumption are at lower risk of experiencing dry eye syndrome. Data from the large Women's Health Study included the self-reported diets of more than 32,400 health professionals as well as their health history. The women were aged between 45 and 84 years old. The study was a cross-sectional study meaning that it took a large sample from a population at a single point in time.
The collected data revealed that the higher the intake of omega-3 fatty acids, the lower the risk of developing dry eye syndrome. The researchers adjusted for age, inclusion in hormone therapy, demographics and total fat intake in the diets. Adjustments were also made for presence of other conditions such as hypertension, diabetes, and joint-related conditions.
Researchers: K. A. Trivedi, et al,
Published: Relation between dietary n-3 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women, American Journal of Clinical Nutrition, October, 2005.
1. B. Miljanovic, K.A. Trivedi, et al., Relation between dietary n-3 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women. American Journal of Clinical Nutrition, 2005 2. Larry J. Alexander, OD, Is There Really a Difference Between Re-esterified Triglyceride and Ethyl Ester Fish Oil?, Advanced Ocular Care, January/February, 2011.
3. J. Dyerberg, P. Madsen, et al., Bioavailability of marine n-3 fatty acid formulations. Prostaglandins, Leukotrienes and Essential Fatty Acids, 2010.