In pursuing ocular surface health, essential fatty acids aren’t merely a beneficial nutritional supplement—they can also aid a topical ophthalmic preparation’s ability to help stabilize the tear film lipid layer, according to a newly published report in The Ocular Surface. It’s all a matter of getting the concentration just right.

A researcher at the University of New South Wales aimed to evaluate essential fatty acids, as well as oleic acid, in eye drops and investigate the biophysical interactions of these acids with meibomian lipids.

Her analysis revealed a number of things about the behavior of essential fatty acids when applied directly to the ocular surface. First, linoleic acid (omega 6) enhanced the spreading of meibomian lipids and increased their compressibility and elasticity—which can help tear stability. Second, alpha-linolenic acid (omega 3) condensed the meibomian lipid film with less elasticity and was deemed unfavorable for tear stability. Third, oleic acid expanded meibomian lipids, but decreased elasticity at high compressions, which makes films less stable. Finally, gamma-linolenic acid had little or no favorable effect on tear stability.

Higher concentrations of fatty acids make films less stable, so the key, according to the research, is low concentrations. “In topical applications, the omega-6 linoleic acid (not omega-3 fatty acid) at low concentrations (20 mol%) can be beneficial for enhancing tear stability in dry eye patients,” the report concludes.

Mudil P. Evaluation of use of essential fatty acids in topical ophthalmic preparations for dry eye. The Ocular Surface. October 4, 2019. [Epub ahead of print].