[1] Natl Univ Singapore, Yong Loo Lin Sch Med, Singapore 117595, Singapore
[2] Natl Univ Hlth Syst, Natl Univ Hosp, Dept Ophthalmol, 1E Kent Ridge Rd,NUHS Tower,Block Level 7, Singapore 119228, Singapore
[3] Natl Univ Hlth Syst, Natl Univ Hosp, Div Plast Reconstruct & Aesthet Surg, Singapore 119228, Singapore