1. School of Optometry, Indiana University, Bloomington, IN, USA
2. Present address: Premier Research, Inc., Durham, NC, USA
3. Mike.Wilkinson@premier-research.com
4. Present address: Vision Science Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, UK
5. rs.anderson@ulster.ac.uk
6. bradley@indiana.edu
7. thibos@indiana.edu