1. Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Department of Preventive Medicine, Graduate School, The Catholic University of Korea, Seoul, Korea.
3. Department of Medicine, Graduate School, Kyung Hee University, Seoul, Korea.
4. Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.