Multifunctionality as design principle for contact lens materials

From synthesis through storage to disposal, contact lenses (CLs) interact with different system environments throughout their functional life cycle. To fulfill their therapeutic purpose, they need to exhibit a distinct behavior in each of them, which is achieved through a combination of different material functions. As such, CL materials are a showcase of highly advanced and mass-produced multifunctional biomaterials. Their great relevance and long history mean that a vast amount of work has gone into the implementation of ever more advanced functions. From understanding the approaches used to achieve multifunctionality in CLs, a lot of inspiration for the design of other multifunctional medical devices can be drawn. Therefore, here, we provide a systematic overview of the different functions that are combined in today’s CL materials, together with their quantification methods, chemical design principles and fabrication techniques. We further provide an outlook on the functions that are currently under investigation for the next generation of commercial CLs.