Tracking trends in blindness and ocular morbidity in India

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. In identifying sentinel sites, the following criteria were used:

• The sentinel unit should have a high turnover of ophthalmic cases.
• The unit should have an infrastructure which would support timely diagnosis, recording and dissemination.
• The unit should be representative of the region where it is located.

25 sentinel units and one National Sentinel unit have been identified and are presently functional. The National Sentinel Surveillance Unit is located at the Dr. Rajendra Prasad Centre for ophthalmic Sciences, All India Institute for Medical Sciences, New Delhi India which is a WHO Collaborating Centre for Prevention of Blindness. The other sentinel units are located in all the major States and Union Territories of the country.

What is Sentinel Surveillance?

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 (WHO). Surveillance is an important public health tool which guides policy formulation and program implementation. Surveillance is of use ONLY if the collected information leads to action that strengthens control of disease.

The WHO is pursuing surveillance as part of a global strategy for preventing and controlling Non Communicable Diseases and the major risk factors that predict them.

Sentinel surveillance is the collection and analysis of data by designated institutions selected for their geographic location, medical specialty, and ability to accurately diagnose and report high quality data (USAID). Sentinel surveillance data may not be representative of the whole population but provides an insight into the overall trends that may be existing and the changes that may be occurring in disease profile and magnitude.

Sentinel surveillance is usually passive as it depends on patients who come to an institution which treats a large number of cases of a particular disease. This has the disadvantage that all persons suffering from a particular disease may not report to this hospital and therefore it cannot capture the experiences of all individuals who suffer.

Therefore sentinel surveillance data should be used judiciously. It should not be taken as an estimate of the disease burden in a country but should be used as an indicator of the prevailing trends in the region / country.

Sentinel Surveillance System for Control of Blindness in India

Objectives of Sentinel Surveillance

• To determine coverage, Cataract Surgery Rate and other parameters reflecting levels of performance in the district including bilateral cases of blindness due to cataract.
• To assess ocular morbidity in the district by collections and compilation of information from various service providers in the district.
• To monitor quality and functional status of equipments and supplies made available to the service units
• To determine the utilization of various facilities and human resources available for eye care in the district.
• To identify reasons for low uptake in those areas where coverage is low.
• To identify barriers in providing optimal services both in quantitative and qualitative terms.
• To assess quality of services by determining success rate in relation to gender, socio economic status, type of surgery, place of surgery and age at the time of surgery.
• To identify complications after surgery
• To assess extent of follow up services
• To work out area specific strategies to improve compliance to follow up.

Organization of Sentinel Surveillance Units

• The SSU would be located in the Department of Community Medicine/ SPM of Medical Colleges with technical cooperation of the Ophthalmology Departments in the same institution.
• One faculty form Community Medicine Department and para-opthalmic personnel and One Medical Social Worker / Health Educator will be responsible for the collection of data.
• Key persons of SSU will be trained in selected institutions in the country on various methods of surveillance.
• Head of the Department of Community Ophthalmology / Community Medicine will be coopted as members of DBCS
• Faculty of SSU and key members of DBCS will met regularly (preferably once a month)

Tasks performed by SSU

• Collection of morbidity data from OPD
• Completion of CSR at government and NGO institutions
• Periodic visual outcome surveys
• Beneficiary assessment.

National Surveillance Unit

The National Surveillance Unit has been set up under assistance from WHO under the Project entitled "Strengthening Management Capacity of National Surveillance Unit under NPCB". There is an urgent need to set up a mechanism, which will plan and implement activities, which will support policy initiatives for control of blindness. There is also a need for coordinating and providing technical support to the sentinel surveillance units in the country. The Unit works in close collaboration with the Ophthalmology Section, Directorate General of Health Services, Government of India.

The objectives of the NSU are as follows:

• To establish a database for all blindness control activities in India.
• To provide technical support for the network of sentinel surveillance units established in the country.
• To disseminate information on trends in blindness control activities in the country, including epidemiology of blindness, quality of surgical outcomes, patterns of eye care service delivery, human resources for eye care and utilization, effectiveness and efficiency of eye care services in the country.
• To monitor and evaluate the impact of sentinel surveillance on development of an evidence base for NPCB.
• To provide technical support, of an advisory nature, for policy formulation and programme implementation in the country.
• To develop information resources and relevant software packages for monitoring and evaluation of programme implementation including mapping of services for end users.
• To act as a clearinghouse for information resources on blindness control in the country.