1. Department of Ophthalmology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Ophthalmology, Kyung Hee University Hospital, Kyung Hee University College of Medicine, Seoul, Korea.
3. Department of Ophthalmology, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Korea.