Lipid in tear film identified

Oleamide, a fatty acid amide, has been identified as a principal component of meibomian gland secretions by researchers at Ohio State University. The discovery may improve the understanding the etiology of ocular disorders such as dry eye disease, according to a press release from the university.

"The finding could give us more insight into the role of lipid activity in humans and may also indicate a new function for oleamide and related lipids in cellular signaling in the eye and in the maintenance of tear film," said Kelly K. Nichols, OD, MPH, PhD, in the release. Dr. Nichols is first author of a paper describing the study, which is published in the February issue of Investigative Ophthalmology & Visual Science.

Dr. Nichols and colleagues used a mass spectrometry technique to analyze samples of meibomian gland secretions taken from healthy volunteers. They measured the accurate mass and collision-induced dissociation in these samples and compared their findings to lipid standards to identify specific lipid species, according to the study.

The study is the first to observe oleamide's presence in the tear film, according to the press release.

"The lack of certain compounds in the tear film may result in a number of different eye-related disorders, including dry eye. The amount of oleamide and related lipids in tear film may be related to these disorders," Dr. Nichols said in the release. "Dry eye is really a disorder of symptoms that irritate the eyes. ... If we could find individuals with varying oleamide levels, then we may be able to discern one cause of dry eye and specifically treat that," she said.