Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China. Hong Kong Eye Hospital, Hong Kong Special Administrative Region, Hong Kong, China. Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Eye Institute, Guangdong Academy of Medical Sciences, Guangzhou, China; and. Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark.