Report of the 4th Global Scientific Meeting on Trachoma, Geneva, 27–29 November 2018

World Health Organization, Geneva, Switzerland

WHO/Department of control of neglected tropical diseases


The 4th Global Scientific Meeting on Trachoma:

  • Recommended that the World Health Organization not change the existing trachomatous inflammation—follicular elimination prevalence threshold;
  • Requested the global trachoma programme to continue to investigate, in national programmes, the role of alternative technical indicators of elimination of trachoma as a public health problem;
  • Recommended that the definition of trachomatous trichiasis be changed to “at least one eyelash from the upper eyelid touches the eyeball, or evidence of recent epilation of in-turned eyelashes from the upper eyelid”. (The change here is the exclusion of trichiasis that affects only the lower eyelid.);
  • Noted that in circumstances where there is evidence of upper eyelid trichiasis with little or no evidence of current or past active trachoma, cases of trichiasis should be assessed (by clinicians with appropriate training and expertise) for alternative aetiologies. This may take into account evidence such as trachomatous scarring of the conjunctiva, superior pannus, Herbert’s pits and entropion, in order to determine whether upper eyelid trichiasis is due to trachoma or not;
  • Recommended that trichiasis surgeons target a cumulative incidence of post-operative trachomatous trichiasis of < 10% by six months for cases that had minor trachomatous trichiasis (≤ 5 eyelashes touching the eyeball) pre-operatively, and < 20% by six months for cases that had major trachomatous trichiasis (> 5 eyelashes touching the eyeball) pre-operatively;
  • Recommended that in order to improve the outcomes of trachomatous trichiasis surgery, Trichiasis surgery for trachoma (1) be revised to include: (i) a section on day one assessment, by the operating surgeon, for under- and over-correction, with instructions on how these conditions should be managed; and (ii) guidance on undertaking audits of trichiasis surgery outcomes at 6 months; and
  • Agreed that to assess whether the elimination prevalence target for trachomatous trichiasis has been reached, national programmes may use: (i) population-based prevalence surveys powered at evaluation-unit level (i.e. populations of 100 000–250 000 people); (ii) house-to-house case searches (which could be integrated with other public health activities); or (iii)a combination of data from multiple adjacent evaluation units. Professional statistical advice should be sought on how best to combine data from multiple evaluation units, with guidance subsequently given to national programmes and their partners.

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