Principles of screening for diabetic retinopathy

The aim of screening is to prevent disease from progressing to a stage where treatment is less likely to succeed or impossible, resulting in permanent damage or even death. However, not all conditions or diseases are suitable for screening and there are many implications for a health service when it undertakes screening.

Public health screening programmes are based on epidemiological evidence and a clear understanding of disease progression and treatment.

Screening interventions are designed to:

• Reduce the risk of a disease or a condition in a clearly defined population
• Detect signs that a disease or condition that might develop in people who otherwise feel entirely well or have no symptoms (are asymptomatic).

Screening tests look for risk markers that indicate a disease might develop or has just started to develop. For this reason, screening programmes will not help most of the people who take part in them as they would not have developed the disease looked for, although they remain at risk. Additionally, for a variety of reasons, some people who do develop the disease unfortunately also may get missed by the screening test.

When screening for a disease is introduced into a health system it is important that medical researchers and policymakers monitor results on the programme’s overall benefits and risks. Implementing screening is a long term undertaking within a health system and requires careful planning. The cost of screening (human and financial) and the resulting required treatments must be considered. Screening must be constantly monitored and revised: a better test may come into existence or new evidence may arise about the relevance and impact of the screening approach being used in the local setting.

Watch the video to learn more about the key public health principles behind screening and how it is applied to control diabetic retinopathy. As you watch, consider how other screening services in your setting compare to what is required for diabetic retinopathy?