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Surface wetting and friction of Kalifilcon A, a novel silicone-hydrogel contact lens.
Ponzini E., Trabattoni S., Stendardo L., Antonini C., Borghesi A., Zeri F., Tavazzi S.
In contact lens (CL) wear, wettability and friction ensure comfort. Their role is even more relevant when the glycocalyx is damaged or absent, increasing the shear stress during blinking. The manufacturer declares that the composition of the novel silicone hydrogel (SiHy) Kalifilcon A and of its blister solution are designed to retain hydration and a smooth wettable surface, also in subjects suffering from CL discomfort and dry eye symptoms. Based on these considerations, Kalifilcon A was compared in vitro with other CLs (two SiHys, two Hys) in a condition of reduced hydration, mimicking a 6 hour wear. To consider the effect of blister solutions, CLs were analysed after a brief rinse and after a 24 hour incubation in saline solution. The results suggest that the wettability of Kalifilcon A is mainly influenced by its SiHy composition. For all CLs, the wettability was worse after incubation than after a brief rinse. In turn, in terms of friction, there is no clear difference both between SiHys and Hys, and between rinsed and incubated CLs. The friction properties of Kalifilcon A are not affected by the incubation, showing an intermediate coefficient when compared to the other CLs.