[1] Univ Sydney, Westmead Hosp, Dept Publ Hlth & Community Med, Sydney, NSW 2006, Australia
[2] Australian Natl Univ, Natl Ctr Epidemiol & Populat Hlth, Canberra, ACT, Australia
[3] Univ Sydney, Westmead Hosp, Dept Ophthalmol, Ctr Vis Res, Sydney, NSW 2006, Australia
[4] Univ Sydney, Dept Publ Hlth, Sydney, NSW 2006, Australia
[5] Univ Sydney, Dept Community Med, Sydney, NSW 2006, Australia
[6] Univ Sydney, Dept Biochem, Sydney, NSW 2006, Australia