1. Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK
2. Department of Arctic and Marine Biology, University of Tromsø, 9037 Tromsø, Norway
3. Department of Optometry and Visual Science, City University London, Northampton Square, London EC1V 0HB, UK
4. Institute of Ophthalmology University College London, 11-43 Bath Street, London EC1V 9EL, UK
5. School of Animal Biology and Oceans Institute, University of Western Australia, Crawley, Perth, Western Australia 6009, Australia