FEB 14, 2008
Dr. Reza Dana, a Harvard Medical School professor and Cornea Service Director at the Massachusetts Eye and Ear Infirmary, and colleagues at the Schepens Eye Research Institute tested three formulations of fatty acids in mice induced with dry eyes: 0.2 percent alpha-linolenic acid (ALA, an omega-3 fatty acid); 0.2 percent linoleic acid (LA, an omega-6 fatty acid); and 0.01 percent ALA combined with 0.1 percent LA.
Some mice received once-a-day treatment with these eye drops, while other mice did not receive any eye drops. The eyes of mice treated with ALA showed significantly decreased dry eye signs and inflammatory changes at both cellular and molecular levels.
Researchers found no beneficial effect of combined LA and ALA formulation. The researchers write that the lack of beneficial effect in this combination may in part be dose dependent. However, they note that the consistent failure of LA to demonstrate any positive effect clinically and cellularly suggests that at least for topical therapy, ALA is preferred.
Topical ALA offers an advantage over oral intake of these fatty acids - no unwanted side effects, the authors note.
"The use of these fatty acids in topical formulations to treat dry eye and potentially other inflammatory ocular surface conditions, would allow more flexibility in dosing without the accompanying systemic, in particular gastrointestinal, adverse effects that can be seen with oral intake of these fatty acids. Further studies are clearly indicated to optimize dosing and formulations that are maximally effective."