A diagnostic instrument to help field graders evaluate active trachoma

Abstract

The SAFE strategy (Surgery for trichiasis, mass treatment with Antibiotics to clear ocular Chlamydia trachomatis infection, and Facial cleanliness and Environmental improvement to reduce transmission) is being used to eliminate trachoma as a public health problem. Decisions on whether or not to implement the A, F, and E components of SAFE are made on the basis of the prevalence of trachomatous inflammation-follicular (TF) in 1-9-year-olds. TF has a precise definition: at least five follicles, each of which is at least 0.5-mm diameter, in the central part of the upper tarsal conjunctiva. Determining whether a follicle has a diameter ≥0.5mm is difficult using magnifying loupes alone. We have developed an ultra-low-cost solution: a follicle size guide that takes the form of a durable printed adhesive sticker which can be fixed to graders' thumb nails for direct size comparison. This tool will be made available to health ministries free of charge. It is anticipated to simplify grader training, increase grader trainee pass rates, and prevent in-service diagnostic drift after training is complete.

Acceptability and perceived utility of different diagnostic tests and sample types for trachoma surveillance in the Bijagos Islands, Guinea Bissau

“…Clinical examination is the current WHO-recommended diagnostic method, with a rigorous standardisation process in place to certify grader competence in population-based prevalence surveys and the development of new tools to further aid diagnostic accuracy. 24 , 25 However, it is also well recognised that clinical signs are poorly correlated with ocular C. trachomatis infection, especially after MDA. 7 Furthermore, as countries move towards postvalidation surveillance, more sustainable diagnostic methods that can be integrated into existing national health systems are needed, especially as it becomes increasingly difficult to train and certify trachoma graders as trachoma prevalence decreases.…”

The simplified trachoma grading system, amended

“… 43 We have omitted the diagram from this paper. Follicle size guides 44 have recently been introduced to help graders to consistently diagnose the presence or absence of trachomatous inflammation—follicular according to the agreed definition.…”

Caixa de ferramentas para a eliminação do tracoma na Região das Américas

“…Cada adesivo tem cinco pontos de 0,5 mm de diâmetro e a cor de fundo lembra o aspecto da conjuntiva inflamada (44). Recomenda-se que a pessoa que realiza o exame proceda da seguinte forma:…”