1. Department of Orthopedic and Trauma Surgery, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
2. Department of Ophthalmology, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
3. Department of Health Sciences, University of Colorado, Colorado Springs, CO 80918, USA
4. Department of Trauma, Reconstructive Surgery and Rehabilitation Medicine, University Medicine Greifswald, Physical and Rehabilitation Medicine, 17475 Greifswald, Germany