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What is the appropriate age range of individuals to be included in a survey to estimate the prevalence of trachomatous trichiasis?
  1. Karimurio Jefitha1,2,
  2. Rono Hillary3,
  3. Richard Le Mesurier1,
  4. Mutuku Mwanthi2,
  5. Jill Keeffe1
  1. 1Department of Ophthalmology, University of Melbourne/Centre for Eye Research Australia, Melbourne, Victoria, Australia
  2. 2Department of Community Health, University of Nairobi, Nairobi, Kenya
  3. 3Northern Rift Valley Zonal Eye Unit, Kitale, Kenya
  1. Correspondence to Dr Karimurio Jefitha, Department of Ophthalmology, University of Melbourne, Level 1, 32 Gisborne Street East, Melbourne, Vic 3002, Australia; j.karimurio{at}


Introduction A survey to determine the prevalence of trachomatous trichiasis (TT) requires a large sample size and the recommended participant age is ≥15 years. This study sought to establish the appropriate age range of individuals to be included in TT surveys.

Methods Data from six previous surveys of adults ≥15 years old were reanalysed.

Results Reanalysis indicated that 69.6–93.3% (average 87.0%) of untreated TT occurred in those aged 40+ years and 52.2–86.7% (average 73.1%) in those aged 50+ years (age ≥50 years is used in rapid assessment of avoidable blindness). Age ≥40 years was adopted in a TT survey conducted in Turkana district because it allowed a smaller sample size than age ≥15 years.

Conclusions The estimated backlog of untreated TT in people aged ≥40 years old in Turkana was 5932 and the overall TT backlog was likely to be 6358–8523. These findings cannot be generalised because all surveys were carried out in the same country.

  • Epidemiology

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  • Funding This study was funded by the Government of Kenya, the European Union, volunteer ophthalmologists from Spain, local communities and community-based organisations.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the Kenya Medical Research Institute/National Ethics Review Committee and the University of Melbourne.

  • Provenance and peer review Not commissioned; externally peer reviewed.