When, Nouryon (former AkzoNobel speciality chemicals), launched a new surfactant with a good dermatological profile, they wanted to prove superior performance vs competitive benchmarks. As the current test methods were not sensitive enough, they turned to an analysis using QSense cleaning profile.
Contact lens should support a continuous tear film for optimum visual clarity. It should also resist the sorption of tear components as deposition can lead to decreased visual clarity and discomfort. Wettability of the surface affects both the tear film as well as biocompatibility of the lens.
You might find it confusing when seeing all the different methods for surface free energy calculations. As surface free energy can give you more information on your surface compared to the contact angle measurements alone, it is time well spent to study the different theories more in detailed.