Prevention of blindness and deafness

Epidemiology and economic analysis

Countries are encouraged, with WHO technical support, to conduct random sample, population-based prevalence and cause surveys of deafness and hearing impairment. Surveys are based on a specially developed WHO Survey Package (protocol, data entry form, coding instructions, dedicated software). The survey protocol is available online. The data-entry form has been updated recently and can be downloaded for use. The software is presently being updated and will be available for use shortly.

A number of surveys based on the WHO survey protocol have been undertaken. The results of these surveys were discussed during a meeting of the key investigators, held in WHO HQ at Geneva in 2003.

Population based surveys to assess prevalence of hearing loss and its causes have been undertaken in: • Brazil (Canoas), • China (Jiangsu, Sechuan, Guizhou, Jilin provinces) • Ecuador • India (Vellore) • Indonesia (Bandung) • Iran (Tehran) • Madagascar • Myanmar (Yangon) • Nigeria (Tana province) • Oman • Sri Lanka • Vietnam (Northern, Southern)

Testing an infant in Africa and a child in Asia during prevalence surveys using the WHO protocol

The data generated will continue to be used in planning, determination of priorities, economic analysis and raising awareness. Results will be used at local and national levels, and collated for regional and global levels. An economic analysis of sensory disabilities was undertaken in 2000 (see below). In the future WHO aims to undertake further research into the economic impact of hearing loss and the cost effectiveness of interventions.

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