Abstract
Purpose: :
To evaluate the relationship between various strongly-adherent proteins bound to the contact lens surface of lenses collected from symptomatic (i.e. reports decreased comfort at replacement time) and asymptomatic patients.
Methods: :
In this study lenses were collected from the symptomatic and asymptomatic patients aseptically and stored dry at below -20 ºC. All patients wore the same non-ionic silicone hydrogel lens material and used the same lens care regimen. Lenses were equilibrated to ambient temperature and incubated for 3 hours in 2 mL of extraction buffer at 50 ºC. Extracts were processed and covalently labeled with a fluorescent dye and analyzed via a microfluidic electrophoresis assay.
Results: :
Symptomatic and asymptomatic patients exhibited statistically significantly different levels of protein sorption of 1.99±1.45 and 1.14±0.47 μg/Lens, respectively (p = 0.037) (student’s t-test, α = 0.05).
Conclusions: :
Various proteins including lysozyme, lactoferrin, lipocalin, albumin and sIgA were resolved by this method. Comparison of the average amounts of each individual protein species deposited on the lens surfaces by both groups exhibited trends by individual protein species, however those protein species which often have been the focus of contact lens research exhibited no significant difference between the symptomatic and asymptomatic patients. Therefore, it appears that proteins other than those resolved by this method, but which nevertheless are accounted for under the total protein sorption value, may be the actual drivers of reported decreases in comfort at time-of-replacement. The interdependence of these and other biomarkers should be the focus of future research toward a fuller understanding of the relationship between patients and reported decreases in comfort at replacement time.
Keywords: contact lens • protein purification and characterization