Aim To investigate the prevalence and causes of optic neuropathy, reported as epidemic in 1997, among secondary school students in Dar es Salaam, Tanzania.
Patients and methods First year students (n = 10 892) from 63 secondary schools located within 30 km from the base hospital were interviewed and had a visual acuity (VA) screening test. Students failing the 6/12-line in either eye were defined as having “poor eyesight” and referred to the base hospital where an optometrist re-tested VA and refracted them. An ophthalmologist examined students with VA of 6/12 or worse in either eye and visual impairment was defined as VA of worse than 6/12 with best correction. Associations between optic neuropathy, socioeconomic status and educational results were investigated.
Results Students' ages ranged from 12 to 22 (mean 15.2) years; 50.6% were male. The prevalence of optic neuropathy was 0.3 (SD 0.051)%. The condition affected older students and was associated with the family having fewer economic possessions (car, computer, television). Optic neuropathy accounted for 19/33 (58%) of bilateral visual impairment cases. No effect of the disease on educational performance was identified.
Conclusion Optic neuropathy remains a significant problem in this population and can now be termed endemic rather than epidemic. Further research into its causes is required.
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Funding This study was funded by the British Council for the Prevention of Blindness (BCPB).
Competing interests None declared.
Ethics approval Ethical approval was granted by the Government of Tanzania through its Medical Research Coordinating Committee and by the Ethics Committee of the London School of Hygiene and Tropical Medicine, UK.
Patient consent Before recruiting students, the study was explained in writing to all parents and students and it was explained again verbally to students on the day of examination. Students agreed to participate by signing a consent form. Parents were asked to inform the head teacher or the study team verbally or in writing if they did not want their child to participate. Children could opt out at any stage without this affecting their normal management.
Provenance and peer review Not commissioned; externally peer reviewed.