Sydney, Australia, 18 November 2016: Contact lens comfort is the end-game for an industry and wearers seeking a lens that sits unnoticed on the eye. Tear lipid sprays and drops are some of the products developed to enhance comfort with contact lenses. But how well do they work?
There is some evidence of improved tear dynamics and ocular comfort using topical lipid supplements during short periods of contact lens wear, but the effect over multiple days is poorly understood.
To learn more, researchers from Brien Holden Vision Institute and the School of Optometry and Vision Science at University of New South Wales Australia tested the performance of a commercial spray and a drop supplement. Tear samples from participants were examined one day after the 3-time daily application of the supplement and then again after 14 days of the 3/day application.
What they found was that neither of these products had an effect on lens wear comfort. The study showed that the majority of the biochemical changes in tears that occurred at day 1 had returned to baseline at day 14, which suggests an effect of prolonged lens wear or that the tear film adapts to this application.
“It was found that the drops showed a transient effect on the tear lipidome (the combination of lipids in the cell) and this action could translate to the short-term relief experienced with use of these drops,” says lead researcher, Dr Athira Rohit.
“The tear film itself is dynamic and responses to supplements will depend on the tear film characteristics of each individual. However, by looking at the relative differences in the tear film between pre- and post-application of the supplements in each patient, we could determine the influence the supplements were having.”
Another useful discovery was that when the concentration of phospholipase (an enzyme that converts phospholipids into fatty acids) in the tear film decreased, comfort increased. Dr Rohit, says this further confirms that a contact lens acts as a stress factor on the tear film.
“Increased levels of phospholipase have been reported in many inflammatory diseases, including ocular surface inflammation and in contact lens intolerance,”she says.
The researchers also found that lysophospholipids, and (O-acyl)-ω-hydroxy fatty acids (OAHFA), which decreased and increased respectively as phospholipase decreased, are potential biomarkers in lens wear discomfort. Dr Rohit says this suggests the possibility of using therapeutic drugs that target those biomarkers in order to improve comfort.
This research was published in the October edition of Optometry & Vision Science:
Rohit A, Willcox MDP, Stapleton F, Effects of Lipid Supplements on Tear Biochemistry in Contact Lens Wearers, Optometry & Vision Science, 2016 Oct;93(10):1203-1209.
