1. Surin Hospital and Surin Medical Education Center, Suranaree University of Technology, Surin 32000, Thailand
2. Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
3. Center of Excellence in Glaucoma, Chulalongkorn University, Bangkok 10330, Thailand
4. Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand