Screening provides a way to detect the presence of an eye disease at an early stage, or risk factors for its development, among larger numbers of people who are asymptomatic (i.e. are not experiencing any symptoms), but are at an increased risk of developing the disease.
Screening differs from diagnostic testing. Diagnostic testing is performed to confirm the presence or absence of a disease among individuals who are experiencing specific symptoms, such as vision loss.
People with diabetes are at increased risk of developing several eye diseases, including Diabetes-related Retinopathy, cataract, and glaucoma. All of these diseases can cause vision loss or blindness in people with diabetes. However, DR is the most common (affecting 1 in 3 persons)4 and the most frequent cause of vision loss in people living with diabetes. DR is also the leading cause of visual impairment and blindness in the working-age population worldwide5, 6.
Many patients with Diabetes-related Retinopathy may not experience any visual symptoms until the later stages of disease when vision loss may be irreversible, even with treatment7. There is strong evidence that the risk of vision loss or blindness from Diabetes-related Retinopathy can be greatly reduced by screening individuals with diabetes for the early signs of sight-threatening Diabetes-related Retinopathy, and ensuring they receive timely access to treatment8.
Screening for Diabetes-Related Eye Diseases
A number of countries have published their own clinical guideline recommendations relating to screening and management of Diabetes-related Retinopathy in people with diabetes (Table 1). Specific recommendations vary between countries, often reflecting differences between healthcare system structure (e.g. private vs public) and levels of health care resources available (e.g. health care personnel, access to diagnostic equipment and treatments).
The two largest global ophthalmology and diabetes societies (the International Council of Ophthalmology [ICO] and the International Diabetes Federation [IDF]) have also published international guidelines for eyes affected by diabetes, which include specific recommendations for screening, diagnosis and treatment of DR (Table 2).
Table 2: International guidelines for screening, treatment and management of diabetic eye disease
A short summary of the ICO and IDF global recommendations relating to screening and referral is provided below: Algorithms detailing the screening recommendations from the ICO and IDF guidelines are shown below (Figures 1 and 2).
Figure 1: Flowchart showing screening for Diabetes-related Retinopathy (ICO Guidelines)