1. From the Department of Ophthalmology, Hanyang University College of Medicine, Guri Hospital, Gyeonggi-do, Korea; the 2Department of Ophthalmology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea;
2. the Department of Ophthalmology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea;
3. the Department of Biostatistics, Yonsei Univesity College of Medicine, Seoul Korea; and
4. the Department of Ophthalmology, University of CHA, College of Medicine, Bundang CHA Medical Center, Gyeonggi-do, Korea.