[1] Chang Gung Mem Hosp, Linkou Med Ctr, Dept Ophthalmol, Taoyuan City 333, Taiwan
[2] Singapore Natl Eye Ctr, Singapore 168751, Singapore
[3] DUKE NUS Med Sch, Singapore 169857, Singapore
[4] Univ Illinois, Illinois Eye & Ear Infirm, Dept Ophthalmol & Visual Sci, Chicago, IL 60612 USA
[5] Chang Gung Univ, Coll Med, Taoyuan City 333, Taiwan