[1] Univ Sydney, Dept Ophthalmol, Westmead Millennium & Save Sight Inst, Westmead, NSW 2145, Australia
[2] Univ Wisconsin, Sch Med, Dept Ophthalmol & Visual Sci, Madison, WI USA
[3] Univ Newcastle, Ctr Biostat & Epidemiol, Newcastle, NSW 2308, Australia