[1] Moorfields Eye Hosp, Glaucoma Serv, 162 City Rd, London EC1V 2PD, England
[2] Natl Univ Hlth Syst, Dept Ophthalmol, Singapore, Singapore
[3] Singapore Eye Res Inst, Singapore, Singapore
[4] Singapore Natl Eye Ctr, Singapore, Singapore
[5] Moorfields Eye Hosp, Biomed Res Ctr Ophthalmol, Natl Inst Hlth Res, London, England
[6] UCL, Inst Ophthalmol, Dept Epidemiol & Genet, London, England