The reliability of anterior segment lesions as indicators of onchocercal eye disease in Guatemala

Kevin L. Winthrop, Roberto Proaño, Orlando Oliva, Byron Arana, Carlos Mendoza, Alfredo Dominguez, Josef Amann, George Punkosdy, Carlos Blanco, Robert Klein, Mauricio Sauerbrey, Frank Richards

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


World Health Organization certification criteria for onchocerciasis elimination use anterior segment eye lesion prevalence as an indicator of mass ivermectin treatment program success. Lesions either contain visible microfilaria (noninflammatory punctate keratitis [PK] or microfilariae in anterior chamber [MFAC]), or microfilaria obscured by inflammation (inflammatory PK). To assess the utility of these disease indicators, two experienced ophthalmologists independently examined persons from endemic (N = 325) and nonendemic (N = 348) Guatemalan communities. Thirty-six (11.1%) and nine (2.6%) persons from endemic and nonendemic areas respectively had lesions found by either ophthalmologist (prevalence ratio = 4.3, 95% CI 2.1-8.8, P < 0.001). All lesions in nonendemic areas were inflammatory PK in whom no persons were seropositive for onchocerciasis. Overall, observer agreement was moderate (Kappa = 0.49), and most (61%) discordance occurred with inflammatory PK lesions. Our findings suggest that inflammatory punctate keratitis is neither a specific nor a reliable indicator of onchocercal eye disease. Future prevalence surveys should rely upon noninflammatory lesions as disease indicators.

Original languageEnglish (US)
Pages (from-to)1058-1062
Number of pages5
JournalAmerican Journal of Tropical Medicine and Hygiene
Issue number6
StatePublished - Dec 2006

ASJC Scopus subject areas

  • Parasitology
  • Virology
  • Infectious Diseases


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