New research shows that those who suffer from dry eyes may improve their symptoms by taking re-esterified omega-3 fatty acid supplements. These findings were carried out by Alice T. Epitropoulos, MD, from Ohio State University in Columbus who presented them at the American Society of Cataract and Refractive Surgery (ASCRS) 2017 Annual Congress and, with others, published in the Cornea.
The chance of experiencing dry eye increases with age. Currently it affects about 5 percent of people 30 to 40, and it affects 10–15 percent of people older than 65, according to the FDA. It’s also more common among women, especially post-menopause.
Although omega-3 supplements are already a standard treatment for dry eyes in the United States, there are few prospective trials testing these supplements in dry eye disease, especially the re-esterified form, which is what this latest study focused on.
Dry eye occurs when the eye does not produce tears properly, or when the tears are not of the correct consistency and evaporate too quickly. In addition, inflammation of the surface of the eye may occur along with dry eye.
Left untreated, dry eye can lead to pain, ulcers, or scars on the cornea, and some loss of vision, according to the Food and Drug Administration. (However, permanent loss of vision from dry eye is uncommon.)
Dry eye can make it more difficult to perform some activities, such as reading for an extended period of time, and it can decrease tolerance for dry environments, such as the air inside an airplane.
In the United States, approximately 3 million people suffer from dry eye and that number is growing. According to cornea specialists, dry eyes have reached epidemic levels. Research conducted by the American Academy of Ophthalmology found that people who spend much time in front of screens simply forget to blink and this sets off a negative reaction.
Every time one blinks the meibomian glands in the eye release a lipid element of the tear film into the eye, which helps retain moisture. On average, people blink every four seconds, and each blink leads to the release of this liquid. But when people forget to blink, their tear film does not function properly. When there isn’t enough lipid within the tear film, the tears cannot quite cover the eyeball, and they evaporate too quickly. This inevitably leads to irritation.
Dry eye symptoms may include any of the following:
- stinging or burning of the eye
- a sandy or gritty feeling as if something is in the eye
- episodes of excess tears following very dry eye periods
- a stringy discharge from the eye
- pain and redness of the eye
- episodes of blurred vision
- heavy eyelids
- inability to cry when emotionally stressed
- uncomfortable contact lenses
- decreased tolerance of reading, working on the computer, or any activity that requires sustained visual attention
- eye fatigue
How Omega-3s Can Help Dry Eye
Omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been shown to raises the levels of fatty acids in the meibomian gland secretions. Because they stay in a liquid form at body temperature, they prevent the blockage of meibomian gland ducts, increasing the quality of the glands' secretions and reducing tear film evaporation.
In addition, omega-3 fatty acids break down into molecules that suppress the inflammatory pathways involved in meibomian gland–related ocular surface disease.
Omega-3 fatty acids occur naturally in fish oil. A retrospective study of 32,470 women showed that those who ate five to six servings of tuna per week were 66% less likely to be diagnosed with dry eye disease than those who ate two or fewer servings, Dr. Epitropoulos and her colleagues, whose finding were published in Cornea, note.
However, most people do not get enough omega-3 fatty acids from eating fish, so fish oil supplements are often recommended by physicians to help control dry eye.
A previous small randomized trial showed significantly better scores in tear breakup time (TBUT), ocular surface disease index (OSDI), meibum expressibility, and meibum quality in people taking fish oil supplements, according to Dr. Epitropoulos.
However, most commercial fish oil supplement producers add alcohol to remove mercury and other toxins from the oil. The alcohol converts the triglycerides in fish oil to an ethyl ester compound that is not found in nature and is difficult to absorb. A handful of fish oil supplements are re-esterified to remove the alcohol; previous research has shown this is more easily absorbed.
Therefore, Dr. Epitropoulos and colleagues wanted to find out whether a re-esterified omega-3 supplement might provide even greater benefits in patients with dry eye disease.
They recruited 105 adults with dry eye disease and meibomian gland dysfunction stage 1 or 2 and a tear osmolarity of at least 312 mOsm/L in at least one eye.
The scientists then randomly assigned 54 of the patients to take 1680 mg EPA and 560 mg DHA re-esterified omega-3 fatty acid daily. The other 51 subjects took 3136 mg safflower oil daily.
Both groups showed improvements in most of these measures at 6 weeks. Safflower oil contains linoleic acid, an omega-6 fatty acid, which may also have benefits for meibomian gland dysfunction. However, at week 12, the improvements in OSDI, tear osmolarity, TBUT, and omega-3 index levels were all greater in the omega-3 group, by a statistically significant margin.
Reducing dry eye is just one of the many ways that omega-3 supplements have been shown to help improve overall health. Research has also shown that omega-3 fatty acids reduce inflammation and may help lower risk of chronic diseases such as heart disease, cancer, and arthritis.