Global burden of blindness is 37 million according to the global blindness data of 2002.

Apart from the prevention strategies for blindness and visual impairment it is crucial to have specific data on risk factors so that priorities can be timely set to intervene and monitor. The concept of blindness surveillance caters to this requirement.

India is the first country to launch a sentinel surveillance system for tracking blindness and ocular morbidity. Available data in the country indicated that there is a need to maintain a constant vigil on performance, quality and implementation of identified strategies. It would not be feasible to set up a monitoring and collating mechanism in all districts in a culturally diverse and heavily populated country like India. It was therefore decided to set up a chain of Sentinel Surveillance Units across the country which would be representative of the different regions.

Surveillance is often defined as the systematic collection, analysis and interpretation of health data and the timely dissemination of this data to policymakers and others. Good quality health information is essential for planning and implementing health policy in all countries. Surveillance provides health information in a timely manner so that countries have the information that they need to fight epidemics now or plan for the future. It is a fundamental tool of public health.

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