John G Pearce1, Rohan W Essex2,3,4, Ted Maddess1. 1. John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia. 2. Academic Unit of Ophthalmology, ANUMS, Canberra, Australia. 3. Department of Ophthalmology, Canberra Hospital, Australia. 4. Royal Victorian Eye and Ear Hospital, Melbourne, Australia.