Blindness in Sudan: Is it time to scrutinise survey methods?
2006

Blindness in Southern Sudan: Survey Methods Under Scrutiny

publication Evidence: moderate

Author Information

Author(s): Hannah Kuper, Clare Gilbert

Primary Institution: London School of Hygiene & Tropical Medicine

Hypothesis

Is the high prevalence of blindness in southern Sudan a result of over-sampling or over-diagnosis?

Conclusion

The prevalence of blindness in southern Sudan is alarmingly high, but the survey methodology may have led to overestimation.

Supporting Evidence

  • The prevalence of blindness in southern Sudan was found to be 4.1%, much higher than the WHO estimate of 1%.
  • Surveys in other postconflict areas report significantly lower blindness rates.
  • The leading causes of blindness identified were cataract and trachoma.

Takeaway

The study found a lot of blind people in southern Sudan, but it might be because the way they counted them wasn't very good.

Methodology

The study discusses the challenges of conducting surveys in low-income settings and the potential biases in participant selection and diagnosis.

Potential Biases

There is a risk of over-sampling blind individuals and misdiagnosing normally sighted individuals as visually impaired.

Limitations

The survey may have overestimated blindness due to biases in participant selection and visual acuity measurement.

Participant Demographics

The survey focused on individuals over five years old in southern Sudan.

Digital Object Identifier (DOI)

10.1371/journal.pmed.0030476

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