1. Corneal Research Group, Singapore Eye Research Institute, Singapore, Singapore;
2. Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore, Singapore;
3. Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore;
4. Ocular Surface Research Group, Singapore Eye Research Institute, Singapore, Singapore; and
5. Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan.