1. From the Singapore National Eye Center, Singapore; the 2Singapore Eye Research Institute, Singapore;
2. From the Singapore National Eye Center, Singapore;
3. the Wilmer Eye Institute and 4The Johns Hopkins Bloomberg School of Public Health, The Johns Hopkins Hospital, Baltimore, Maryland; and
4. the Singapore Eye Research Institute, Singapore;
5. the Singapore Eye Research Institute, Singapore; the 5Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.