Evaluation of in vitro contact lens friction: Effects of recombinant human proteoglycan 4 and test counterface

In vitro contact lenses friction significantly correlates with contact lens discomfort. In this thesis, in vitro friction testing was conducted to evaluate the effects of recombinant human PRG4 (rhPRG4) as an ocular surface boundary lubricant and to evaluate both biological and synthetic test counterfaces. The objectives were to (1) assess the potential effect of different lens types and incubation times on the friction of rhPRG4-incubated contact lenses and (2) evaluate mucinsoaked PDMS as a synthetic test counterface for in vitro friction testing of contact lenses. Results of this thesis work demonstrated that a) rhPRG4 may be useful as a friction reducing lubricant on some, but not all, silicone hydrogel contact lenses; and b) as a synthetic counterface, PDMSmucin can exhibit similar friction coefficients compared to biological counterfaces on certain silicone hydrogel lenses. Overall, results led to an improved understanding of PRG4 and in vitro contact lens friction.