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The association between refractive cutoffs for spectacle provision and visual improvement among school-aged children in South Africa
  1. Nathan G Congdon1,
  2. Nita Patel2,
  3. Paul Esteso3,
  4. Florence Chikwembani4,
  5. Fiona Webber4,
  6. Robert Bongi Msithini4,
  7. Amy Ratcliffe5
  1. 1
    Department of Ophthalmology and Visual Science, Chinese University of Hong Kong, Hong Kong SAR
  2. 2
    Helen Keller International, New York, USA
  3. 3
    Johns Hopkins University School of Medicine, Baltimore, USA
  4. 4
    Vision Care, Umtata, South Africa
  5. 5
    Wolfson Research Institute, Durham University, Durham, UK
  1. Dr Nathan Congdon, Chinese University of Hong Kong, Department of Ophthalmology and Visual Sciences, Hong Kong Eye Hospital 3/F, 147K Argyle St., Kowloon, Hong Kong SAR; ncongdon{at}


Objectives: To evaluate different refractive cutoffs for spectacle provision with regards to their impact on visual improvement and spectacle compliance.

Design: Prospective study of visual improvement and spectacle compliance.

Participants: South African school children aged 6–19 years receiving free spectacles in a programme supported by Helen Keller International.

Methods: Refractive error, age, gender, urban versus rural residence, presenting and best-corrected vision were recorded for participants. Spectacle wear was observed directly at an unannounced follow-up examination 4–11 months after initial provision of spectacles. The association between five proposed refractive cutoff protocols and visual improvement and spectacle compliance were examined in separate multivariate models.

Main outcomes: Refractive cutoffs for spectacle distribution which would effectively identify children with improved vision, and those more likely to comply with spectacle wear.

Results: Among 8520 children screened, 810 (9.5%) received spectacles, of whom 636 (79%) were aged 10–14 years, 530 (65%) were girls, 324 (40%) had vision improvement ⩾3 lines, and 483 (60%) were examined 6.4±1.5 (range 4.6 to 10.9) months after spectacle dispensing. Among examined children, 149 (31%) were wearing or carrying their glasses. Children meeting cutoffs ⩽−0.75D of myopia, ⩾+1.00 D of hyperopia and ⩾+0.75 D of astigmatism had significantly greater improvement in vision than children failing to meet these criteria, when adjusting for age, gender and urban versus rural residence. None of the proposed refractive protocols discriminated between children wearing and not wearing spectacles. Presenting vision and improvement in vision were unassociated with subsequent spectacle wear, but girls (p⩽0.0006 for all models) were more likely to be wearing glasses than were boys.

Conclusions: To the best of our knowledge, this is the first suggested refractive cutoff for glasses dispensing validated with respect to key programme outcomes. The lack of association between spectacle retention and either refractive error or vision may have been due to the relatively modest degree of refractive error in this African population.

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  • Funding: This research was supported by funding from USAID (HFP-A-00-01-00027-00) provided to Helen Keller International.

  • Competing interests: The authors have no financial interest in the devices and techniques reported in this manuscript.