The Dry Eye Zone

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Abstract: Tear film biomarkers

Compositional Profiling and Biomarker Identification of the Tear Film.
Ocul Surf. 2008 Oct;6(4):175-185.
Jacob JT, Ham B.

ABSTRACT Identification of tear film proteins and lipids is important for the elucidation of contact lens incompatibilities, tear film instabilities, dry eye syndromes, and other eye diseases. Compositional analysis of the tear film has been hampered in the past by the complex nature of the fluid and small sample size. Previously, all analytical methods required pooling of tear samples and molecular manipulation for detection of proteins and lipids, all of which skewed the resultant data. With the advent of nanoscale detection and analysis methods, it has become possible to identify specific tear components. This paper reviews the recent advances in tear sampling, proteomics, and lipidomics. Compositional profiling techniques, such as multi-dimensional electrophoresis, high performance liquid chromatography, and mass spectrometry, are assessed. Application of these techniques to identify potential biomarkers for specific tear disease conditions, such as blepharitis and dry eye, are evaluated.

I finally strained the budget and renewed my subscription to The Ocular Surface.... nice to be able to read the whole thing agin. This article is an in-depth review of advances in understanding tear film composition better.

For those of you who wonder why there isn't a "cure" for dry eye yet... thought you might be interested in this statement from the article's introduction, showing just how far we have to go on understanding the tear film itself, lot alone how to fix it:

...We currently have very little definitive information regarding which specific elements change in response to glandular disease or environmental issues. Nor do we know the concentrations of these elements that can induce physiological changes in the tear film. Although the signs and symptoms of tear film instability have been fairly well characterized, the specific etiology and physiological changes responsible for that instability are not well known.