1. VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA
2. Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
3. Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA, USA
4. Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
5. Department of Biostatistics, University of Iowa, Iowa City, IA, USA
6. Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA