1. Department of Ophthalmology and Visual Science, Buchon St. Mary's Hospital, College of Medicine, Catholic University of Korea, Buchon, Korea
2. Department of Biostatistics, Department of Preventive Medicine, College of Medicine, Catholic University of Korea, Seoul, Korea
3. Department of Ophthalmology and Visual Science, St. Vincent's Hospital, College of Medicine, Catholic University of Korea, Suwon, Korea