Author: Vanessa Caceres Contributing Editor
Excerpt from: EyeWorld Newsmagazine of the American Society of Cataract & Refractive Surgery, September 2006
Omega-3 acids may help alleviate some of your dry-eye patients’ symptoms.
Still, the quantity of omega-3 acids that patients need for lasting benefits are under investigation.The connection between nutrition and dry eye has only recently been spotlighted. Ophthalmologists tend to focus on clinical concerns versus nutritional treatment, physicians said.
Yet with the press that surrounds the overall nutritional value of omega-3 fatty acidsincluding the link between increased consumption of omega-3 acids and a lower incidence of dry eyethe latest research is hard to ignore, said Robert L. Latkany, M.D., Dry Eye Clinic, New York Eye and Ear Infirmary, New York.
The possibility of nutritional healing will intrigue patients that want to avoid medicine when possible, Dr. Latkany said. “Some patients like medicine but others want this [kind of information]. Those patients love to hear dietary suggestions,” he said.Here is a roundup of some of research from physicians that have explored dry eye and the omega-3 connection.
Much of the research thus far has focused on omega-3 versus omega-6 fatty acids and how they are linked to the incidence of dry eye. Omega-3 acids are found in walnuts and oily, cold, dark fish such as tuna and salmon. Omega-6 acids are found in meat, canola and corn oil, and margarine. Although both kinds of fats are needed to function, omega-3 acids are healthier than the omega-6 acids, said James McCulley, M.D., professor and chair of ophthalmology, University of Texas Southwestern Medical Center, Dallas. Although humans evolved on a diet with an omega-6 to omega-3 acid of one, omega-6 consumption in the typical Western diet can outweigh omega-3 acids by 16 times, according to a study from the October 2002 issue of Biomedicine and Pharmacotherapy.
“We know our diet is relatively deficient in omega-3 fatty acids. Its analogous to good and bad cholesterol, where the omega 6 is the bad cholesterol and the omega-3 is the good cholesterol. We need both, but we need the ratio to be appropriate,” Dr. McCulley said.
Omega-3 acids may benefit dry eye by reducing inflammatory activity in the body and by possibly altering the lipid profiles of the meibomian glands. Some components of the omega-3 acids are thought to stimulate aqueous tear secretion.
“Scientific research over the past decade has shown that specifically targeted nutritional supplements can restore function to the glands that provide lubrication to the eye. This includes both omega GLA as well as omega 3 EPA,” said Spencer P. Thornton, M.D.
Studies and Anecdotal Reports
A study published last year in the American Journal of Clinical Nutrition, led by Biljana Miljanovic, M.D., Division of Preventive Medicine, Brigham and Womens Hospital, Boston, and fellow investigators further connected omega-3 acids to dry eye. Investigators used a food-frequency questionnaire with 32,470 women ages 45 to 84 participating in the Womens Health Study, which is assessing risk factors related to cardiovascular disease and cancer.
After adjusting for demographics, hormone therapy, and total fat intake, investigators found different dietary patterns in the 1,546 women with clinically diagnosed dry eye versus the rest of the group.
“Women with a higher intake of [omega-3 fatty acids] tended to have a lower risk of dry-eye syndrome than did women with a lower intake,” the investigators wrote. They also found the participants to be at a higher risk for dry-eye syndrome if they had a higher dietary consumption of omega-6 acids. Increased tuna consumptionat leastfive to six times a weekseemed to decrease the risk for dry eye in the study, compared with the participants who ate tuna only once a week or less frequently.
Another study published in the February 2003 issue of the European Journal of Clinical Nutrition found that patients with Sjögrens syndrome had a lower intake of omega-3 acids.
Those who treat dry eye find the results from the studies intriguing but want to see more information. “These studies need to be backed with clinical data, which is currently lacking,” said Colin C.K. Chan, M.D., F.R.A.N.Z.C.O., refractive and corneal surgeon, The Eye Institute, Chatswood and Bondi Junction, Australia.
Dr. Chan was involved with an omega-3-related study at the Boxer Wachler Vision Institute, Beverly Hills, which found that 3,000 mg a day of omega-3-rich flaxseed oil one week before and one week after LASIK was just as effective as doxycycline for dry eye when patients were seen three months post-op. He presented the studyresults at this years ASCRS•ASOA Symposium & Congress.
“The study found that there was no difference in dry-eye outcomes between the 79 patients treated with flaxseed oil and the 73 patients treated with doxycycline. More importantly, no patient in the flaxseed oil group had anything more than mild dry eye at three months,” Dr. Chan said.