Two recent studies from ARVO took a look at the effect certain lipids have on contact lens discomfort (CLD), and the results showed a noteworthy correlation. In one study, researchers from the University of New South Wales in Sydney, Australia, compared the degree of saturation and fatty acid chain length of major meibum- and tear-related lipid classes in contact lens wearers with CLD symptoms against wearers without CLD symptoms.1
Of the 42 patients evaluated, the 50% who were symptomatic for CLD had higher concentrations of polyunsaturated fatty acids and long-chain fatty acids in both their meibum and tears compared with asymptomatic patients. According to the study, these “could potentially alter tear film viscoelasticity and increase tear evaporation.”1
“These data should offer additional strategies to minimize dryness in lens wearers,” says Joseph P. Shovlin, OD, of Scranton, PA. “For example, arachidonic acid acts as a precursor of inflammatory mediators, likely influencing symptomatology. Higher levels of lipid that are less stable and susceptible to degradation result in more symptomatic lens wear.”
Another study set out to determine the influence of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and malondialdehyde (MDA) on CLD.2 At the University of Alabama at Birmingham, researchers used various assays to assess concentrations of these lipid mediators in the tears of 20 symptomatic and 20 asymptomatic patients.
Results demonstrated a significant concentration of LTB4 molecules in symptomatic wearers compared with asymptomatic wearers, suggesting it “could possibly be considered a biomarker for CLD with further validation,” and that “inflammation of the front surface of the eye is present in contact lens wearers with discomfort, although it is not readily visible under regular clinical examination,” the study said.2
For now, the researchers suggest practitioners look for LTB4 in the tears of patients with CLD to determine if inflammation is the culprit and treat accordingly.
“Several studies have shown lipid mediators of inflammation such as prostaglandin E2, leukotriene B4 and malondialdehyde are involved in the pathogenesis of CLD,” says Dr. Shovlin. “Subclinical biomarkers may someday be used in clinical practice to provide validation for the influence and effects of inflammation in symptomatic contact lens wearers. Topical medications may be used to block the cascade before symptoms erupt.”
1. Siddireddy JS, Vijay AK, Tan J, Willcox M. Do the saturation and fatty acid chain length of meibum and tear lipids determine symptoms in contact lens wearers? ARVO 2018. Abstract 1747.