1. From the Vision Science Group, Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, and the
2. Department of Ophthalmology, School of Medicine, Mason Eye Institute, University of Missouri-Columbia, Columbia, Missouri; the
3. Department of Ophthalmology, Ulleval University Hospital, Oslo, Norway; the
4. Department of Pathophysiology of Vision and Neuroophthalmology, University Eye Hospital, Tu¨bingen, Germany; the
5. National Eye Institute, National Institutes of Health, Bethesda, Maryland; and the
6. Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Australia.