Status: In progress
To evaluate the reliability of the trachomatous scarring (TS) examination data collected from trichiasis (TT) cases in surveys and determine the potential impact of different levels of agreement on the burden of TT.
This cross-country study in Ethiopia, Uganda and Nigeria will examine the validity and reliability of TS data associated with TT cases from prevalence surveys undertaken in high and low burden settings. The TS ‘survey’ data from 400 TT cases will be compared with an independent expert re-assessment (masked to TS ‘survey’ status) and grading of high-resolution digital photographs of the tarsal conjunctiva to estimate:
To reduce any systematic bias in photograph grading the set of photos for grading will include an additional 100 people (frequency matched by age, sex, and location to quarter of the TT cases) from the original survey without TT.
The study will also investigate the relationship between:
The results of the study will contribute to ongoing debate over whether the definition of TT for the purpose of defining prevalence targets for “elimination as a public health problem”, should be revised to include a specific reference to and dependency on the presence of TS.