1. From the School of Biomedical Sciences, University of Ulster, Coleraine, United Kingdom; the 2Cathedral Eye Clinic, University of Ulster, Belfast, Northern Ireland, United Kingdom;
2. the NH&MRC (National Health and Medical Research Council) Centre for Clinical Eye Research, Department of Optometry and Vision Science, Flinders Medical Centre and Flinders University of South Australia, Bedford Park, South Australia, Australia; and
3. the Cathedral Eye Clinic, University of Ulster, Belfast, Northern Ireland, United Kingdom; the 4Mater Hospital, Belfast Health and Social Care Trust, Belfast, Northern Ireland, United Kingdom.