[Page 23] Correspondence: Conflict of Interest: The authors report no conflicts of interest. Choi Mun Chan, MBBS Contributions: All authors contributed equally. Singapore National Eye Centre Accepted for Publication: May, 2018 11 Third Hospital Avenue This work is licensed under a Creative Commons Attribution Singapore 168751 Non-Commercial 3.0 License (CC BY-NC 3.0). E-mail: chan.choi.mun@snec.com.sg ©Copyright Chan et al., 2018. Phone: (65) 6322-8330 Licensee Ophthoscience Publishers, USA [Page 24] [Page 25]