1. Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway 2The Norwegian Dry Eye Clinic, Oslo, Norway
2. Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
3. The Norwegian Dry Eye Clinic, Oslo, Norway
4. Department of Information Engineering, University of Padova, Padova, Italy
5. Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway 2The Norwegian Dry Eye Clinic, Oslo, Norway 5Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts