1. Department of Optometry and Visual Science, Buskerud University College, Institute of Optometry and Visual Science, Kongsberg, Norway 2Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway
2. Harvard Medical School Schepens Eye Research Institute, Boston, Massachusetts
3. Department of Optometry and Visual Science, Buskerud University College, Institute of Optometry and Visual Science, Kongsberg, Norway