1. Comprehensive Eyecare of Central Ohio, Westerville, OH 43082, USA
2. Department of Ophthalmology, Ohio State University, Columbus, OH 43201, USA
3. The Midwest Center for Sight, Des Plaines, IL 60016, USA
4. Chicago Cornea Consultants, Highland Park, IL 60035, USA
5. New York Medical College, Valhalla, NY 10595, USA
6. Northwest Eye Surgeons, Seattle, WA 98133, USA