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Michelle Senchyna, Howard A. Ketelson, James W. Davis; Exploratory Analysis of the Kinetic Rewetting Properties of an Experimental Disinfection Solution on Silicone Hydrogel Lenses. Invest. Ophthalmol. Vis. Sci. 2011;52(14):6509.
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© ARVO (1962-2015); The Authors (2016-present)
Current methods used to determine advancing contact angles (CA) typically rely on a single data point. This can be a disadvantage when measuring CAs on dynamic surfaces such as contact lenses, which are generally not at thermodynamic equilibrium in their use environment. These effects are the result of changes in surface chemistry over time due to the migration of hydrophobic groups to the air/lens interface. Alternative methods are needed to fully characterize the kinetic wetting and non-equilibrium effects that may occur on silicone hydrogel (SH) surfaces. This study summarizes an exploratory analyses of kinetic rewetting CA data generated from human worn (16 hours) SH lenses (PureVisionTM (PV) and Acuvue® OasysTM (AO)), treated with either an Alcon disinfection test solution (ADTS) or ReNu® MultiplusTM (RMP) (Bausch & Lomb) for seven days.
Advancing contact angle data were collected from captive bubble videos using OCA20-Beta software which was developed to extract angles and diameters from an intersection defined by the operator. Those contact angles measured between 100 sec and 200 sec were considered representative of lens rewetting for each lens-solution combination and were statistically analyzed by area under the curve (AUC) comparison. The outcome variable calculated was considered to describe the captive bubble test as a "kinetic rewetting rate" test, as water advances across the surface. OD and OS lens data were analyzed separately.
AUC comparisons demonstrated solution differences for the most hydrophobic lens material, PV, with ADTS data (OD: 5118±596; OS: 4701±1035) significantly different from RMP (OD: 5672±730; OS: 5589±793) (p<0.05). Mechanistically, these data translate to differences in the efficiency by which water rewets the lens surface. No differences were found between ADTS (OD: 4652±903; OS: 4601±1096) and RMP (OD: 5019±553; OS: 4744±651) for AO lenses.
We present a novel method whereby a kinetic rate of dewetting can be calculated. Results demonstrated that for the most hydrophobic lens material, PV, the Alcon test solution significantly increased the rate of rewetting compared to RMP following 16 hours of wear.
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