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Two strategies for correcting refractive errors in school students in Tanzania: randomised comparison, with implications for screening programmes
  1. S Wedner1,
  2. H Masanja2,
  3. R Bowman3,
  4. J Todd4,
  5. R Bowman5,
  6. C Gilbert1
  1. 1
    International Centre for Eye Health, London School of Hygiene and Tropical Medicine, London, UK
  2. 2
    Ifakara Health and Development Research Centre, Ifakara, Tanzania
  3. 3
    Tanzanian Society for the Blind, Dar es Salaam, Tanzania
  4. 4
    Infectious Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, London, UK
  5. 5
    CCBRT Hospital, Dar es Salaam, Tanzania
  1. S Wedner, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; susanne.wedner{at}


Purpose: To compare whether free spectacles or only a prescription for spectacles influences wearing rates among Tanzanian students with un/undercorrected refractive error (RE).


Design: Cluster randomised trial.

Setting: 37 secondary schools in Dar es Salaam, Tanzania.

Participants: Distance visual acuity was measured in 6,904 year-1 students (90.2% response rate; median age 14 years; range 11–25 years) using a Snellen E-chart. 135 had RE requiring correction.

Interventions: Schools were randomly allocated to free spectacles (arm A) or prescription only (arm B).

Primary outcome: Spectacle use at 3 months.

Results: The prevalence of un/undercorrected RE was 1.8% (95% CI: 1.5 to 2.2%). At 3 months, 27/58 (47%) students in arm A were wearing spectacles or had them at school compared with 13/50 (26%) in arm B (adjusted OR 2.4, 95% CI 1.0 to 6.7). Free spectacles and myopia were independently associated with spectacle use.

Conclusions: The low prevalence of un/undercorrected RE and poor uptake of spectacles, even when provided free, raises doubts about the value of vision-screening programmes in Tanzanian secondary schools. Policy decisions on school vision screening in middle- and low-income countries should take account of the cost-effectiveness as well as competing demands for scarce resources.

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  • Funding: British Council for the Prevention of Blindness (BCPB).

  • Competing interests: None.