[1] Western Sydney Univ, Bathurst Rural Clin Sch BRCS, Sch Med, POB 9008, Bathurst, NSW 2795, Australia
[2] Univ KwaZulu Natal, African Vis Res Inst, Discipline Optometry, Westville Campus, ZA-3629 Durban, South Africa
[3] Univ Cape Coast, Coll Hlth & Allied Sci, Sch Allied Hlth Sci, Dept Optometry & Vis Sci, Cape Coast, Ghana
[4] Univ Calabar, Coll Med Sci, Fac Allied Med Sci, Dept Publ Hlth,Hlth Educ & Hlth Promot Unit, Calabar, Cross River Sta, Nigeria
[5] Kwame Nkrumah Univ Sci & Technol KNUST, Coll Sci, Dept Optometry & Visual Sci, Kumasi, Ghana
[6] Univ Highlands & Isl, Ctr Hlth Sci, Dept Optometry, Inverness IV2 3JH, Scotland
[7] Univ Calabar, Dept Publ Hlth, Epidemiol & Biostat Unit, Calabar, Nigeria
[8] Western Sydney Univ, Sch Hlth Sci, Campbelltown, NSW 2560, Australia
[9] Roberts Eyecare Associates, Vestal, NY USA
[10] Univ Otago, Dunedin Sch Med, Dept Med, Dunedin, New Zealand
[11] Univ Free State, Dept Optometry, Bloemfontein, South Africa
[12] Univ Hosp, Bloemfontein, South Africa
[13] Koforidua Reg Hosp, Koforidua, Eastern Region, Ghana
[14] Univ New South Wales, Sch Optometry & Vis Sci, Sydney, NSW, Australia