1. Department of Viroscience; Erasmus MC; Rotterdam the Netherlands
2. Anova Health Institute; Johannesburg Tzaneen South Africa
3. Rotterdam Eye Hospital; Rotterdam The Netherlands
4. Department of Ophthalmology; VU University Medical Center; Amsterdam the Netherlands
5. Department of Infectious Diseases; University of Cape Town; South Africa
6. School of Public Health and Family Medicine; University of Cape Town; Cape Town South Africa