1. Division of Ophthalmology, University of Stellenbosch, Cape Town, South Africa
2. Division of Ophthalmology, University of Cape Town, Cape Town, South Africa
3. Division of Ophthalmology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, South Africa
4. Centre for Evidence Based Health Care, Department of Global Health, University of Stellenbosch, Cape Town, South Africa