1. Department of Ophthalmology, Chang Gung Memorial Hospital, Chiayi 613, Taiwan
2. College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
3. Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
4. Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY 10032, USA
5. Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung 204, Taiwan