Using Diabetic Retinopathy Care Process Model to Evaluate Interventions

Diabetic retinopathy (DR) is a diabetes complication that affects eyes. It is also the leading cause of blindness for working-age Americans. Early detection, timely treatment, and appropriate follow-up care reduce the risk of severe vision loss from DR by 95%. Unfortunately, less than 50% of people with diabetes follow the recommended screening guidelines.

In this work, the research team built a Diabetic Retinopathy Simulation model to test two interventions to the current eye care process:

  • Intervention 1. primary care DR screening.
  • Intervention 2. primary care screening with care coordination.

The interventions aimed to increase access to screening and reduce the number of low-risk patients using primary eye care unnecessarily.

From the care-process perspective, Intervention 1 filters patients by risk of vision-threatening DR one step earlier in the care path, consequently reducing downstream appointments in specialty eye care. In care coordination (Intervention 2), a medical professional works with patients to help them understand their diagnosis, find a primary eye care provider, and make appointments.

Overall, the purpose of this work is to make evidence-based comparisons between two proposed Interventions and the current care process guidelines. The research team used patient health outcomes, adherence behavior, and cumulative totals of visits to decide about:

  • The impact of moving DR screening to primary care.
  • Using care coordination for patients at risk of the most severe outcomes of DR.

About the Model

The DR care process model was built at North Carolina State University using AnyLogic Personal Learning Edition 8.5.1 software.

Each care process (Interventions 1 and 2) was compared using metrics from both the patient’s perspective (adherence, screening results, and health outcomes) and the provider’s perspective (the number of care visits).


The DR care process simulation model showed that the interventions increased the number of patients with vision-threatening DR who followed eye care recommendations. It also showed a decrease in the number of ‘unnecessary’ visits to eye care specialists from patients without vision-threatening DR and a decrease in the total years a patient spent blind.

Eye care process model

Interactions that occur between
patients (blue) and providers (green).
Points of interventions are in yellow

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