a Department of Ophthalmology, Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany bInstitute of Polymer Materials, Universität Erlangen-Nürnberg, Martensstraße 7, 91054 Erlangen, Germany
Received 15 September 2016, Accepted 23 October 2016, Available online 26 October 2016.