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Published: 21.05.2024
Bhavisha Virendrakumar Research Associate, Evidence Synthesis
Elena Schmidt Director of Evidence, Research and Innovations
Monicah Bitok Global Technical Lead Eye Health,
Diabetic retinopathy evidence gap map table

Diabetic Retinopathy Evidence Gap Map

Diabetes is a global health challenge, and its complications impact various parts of our body including the eyes. Diabetic Retinopathy (DR), a leading cause of blindness, emerges from diabetes-related damage to the retinal blood vessels. Effective screening, early detection, and timely intervention are crucial to prevent and minimise the impact of DR. Addressing this serious condition requires robust evidence-based strategies, which is where Sightsavers’ Diabetic Retinopathy Evidence Gap Map comes into play.

The role of Sightsavers’ Evidence Gap Map

Evidence gap maps (EGMs) are an exciting tool: as well as showing where evidence relevant to low- and middle-income countries exists, the maps make clear where the ‘gaps’ in the evidence are. It is an interactive, online tool that allows users to explore the research landscape in detail. It categorises systematic/literature reviews into themes and sub-themes, making it easy to navigate. It further allows users to understand which evidence they can rely on based on the confidence level attributed to each review: high, medium or low (see figure 1).

Figure 1: Diabetic retinopathy evidence gap map

The EGM serves multiple purposes:

  • Mapping research evidence: It provides an overview of systematic or literature reviews related to DR relevant to low- and middle-income countries, covering various aspects such as prevalence, risk factors, treatment, and screening methods.
  • Identifying gaps: The map highlights areas where more research is needed, guiding researchers and policy makers to focus their efforts on filling these gaps.
  • Inform policy and practice: The map fosters collaboration among researchers, clinicians, policy makers, and non-governmental organisations by providing a shared platform for understanding the current research landscape.

What is included in the DR EGM?

The DR EGM encompasses 124 reviews across the five thematic areas, including on diabetic macular edema. The EGM reveals some important insights into the current state of research on DR. Here is a summary of they key messages:

  1. Detection

One of the most well-studied areas in the EGM is the detection of DR. This area has seen a rapid adoption of new technologies, like digital diagnosis and artificial intelligence, aimed at improving accuracy and efficiency. However, despite the large number of systematic/literature reviews in this area, the varying quality of these shows that more high-quality research is needed.

  1. Treatment

Out of 33 reviews on the treatment of DR, only four were deemed high quality. This indicates that most research in this area lacks the rigor needed to draw strong conclusions. A more robust approach to studying treatments could lead to better outcomes for patients.

  1. Access to services

Three reviews focused on access to services for people with DR. These reviews revealed important findings but should be analysed with caution because their methodological quality ranged from low to medium. Access to services is a critical factor in managing DR, and more high quality reviews could lead to improvements in this area.

  1. Equity

The EGM highlighted a significant gap in research on equity. None of the reviews focused on gender equity, and there is a general lack of reviews on the prevalence of DR and access to services in different population groups. This gap indicates a need for more inclusive research to ensure everyone has equal access to care and treatment.

  1. Health systems

No reviews focus on health systems, which is another critical gap. Systematic or literature reviews covering factors related to human resources, financing, leadership, monitoring and technologies within the health systems is critical to help improve the overall care for people with diabetes.


Sightsavers’ DR EGM provides a comprehensive overview of existing systematic/literature reviews and highlights where more work is needed. The key messages from the EGM point to significant gaps in high-quality reviews, particularly in the areas of treatment, access to services, equity, and health systems. Addressing these gaps is essential to improve care for people with DR and reduce the risk of vision loss.