1. Oklahoma College of Optometry, Northeastern State University, Tahlequah, Oklahoma, USA,
2. Department of Ophthalmology, School of Medicine, University of Colorado, Aurora, Colorado, USA,
3. EyeCare Associates of South Tulsa, Tulsa, Oklahoma, USA,
4. Nicholas Eye Clinic, Enid, Oklahoma, USA,
5. Robert J. Dole Veterans Affairs Medical Center, Wichita, Kansas, USA,