17 January 2011
Pilot , Prospective, Randomized , Double-masked , Placebo-controlled Clinical Trial of an Omega-3 Supplement for Dry Eye
Wojtowicz , J. et al., Cornea , 30 : in press , 2011
Dept. of Ophthamology , The University of Texas Southwestern Medical Ctr. at Dallas, Texas , USA
Dry eye syndrome (DES) is an eye disease caused in part by decreased tear production with typical symptoms including assorted eye irritations including dryness, burning , itchy feeling , fatigue, pain, redness, and excessive sensitivity to bright light. If the condition becomes severe or is not successfully treated , it can produce complications leading to eye damage. The prevalence of DES increases with age in the population such that up to 30 % of people over age 50 in some regions suffer from this condition .
In the present study, patients with dry eye were treated with daily omega-3 supplementation consisting of 300 mg DHA plus 450 mg EPA plus 1000 mg flaxseed oil for a duration of 90 days. A total of 36 patients were clinically evaluated at baseline (entry) and at the end of the study. Tear secretion and tear volume was also assessed ( by Schrimer testing and fluorophotometry ). When the supplementation trial ended, 70 % of the patients in the treatment group become symptom-free as compared to only 7% of those on the placebo (control) group. Further, the average tear production and tear volume was increased in the omega-3 group
Dr. Holub’s Comments :
Is is noted that the omega-3 supplementation regimen included DHA plus EPA from fish oil sources plus 1000 mg of flaxseed oil which would have been expected to provide approx. 500 mg of LNA (alpha-linolenic acid) . Since DHA and EPA , and not LNA, are the precursors for the formation of the anti-inflammatory bioactive products known as resolvins and protectins , it remains to be determined to what extent , if any, the presence of the plant-based omega-3 (ie, LNA from flax) may have contributed to the overall favourable effects. It is known that the human body has a very limited capacity to metabolically convert LNA to EPA/DHA. Very recently, research using a dry eye mouse model (after exposing the mice to dessicating conditions) has revealed that the direct topical application of resolvin E1 (as derived from EPA omega-3) was found to significantly improve tear production and to decrease inflammation (Li et al., J. Ocular Pharm. and Therapeutics, 26: 431-439 (2010). These findings suggest that such omega-3 products , resolvins and protectins, may have therapeutic potential in treating DES.