Diabetic Retinopathy: Understanding the 2D Capillary Field & VEGF Diffusion Map

What Diabetic Retinopathy Is

Diabetic retinopathy is a complication of diabetes that damages the blood vessels in the retina, leading to vision impairment. It occurs due to high blood sugar levels over time, causing damage to small blood vessels in the eye’s light-sensitive tissue called the retina.

The condition can progress through several stages, from mild non-proliferative retinopathy (where small areas of the retina become damaged) to severe proliferative retinopathy (where new abnormal blood vessels grow on the surface of the retina).

How the 2D Capillary Field Model Works

The model simulates a grid representing the capillary network in the retina, with each cell symbolizing a capillary unit guarded by pericytes. Pericytes are essential cells that help regulate blood flow and protect the integrity of the blood-retinal barrier.

Under hyperglycemic conditions, these capillaries begin to decay, leading to ischemia (lack of oxygen) in the retina. This process is modeled through a reaction-diffusion mechanism where pericyte loss triggers a cascade of events including VEGF (vascular endothelial growth factor) diffusion and subsequent neovascularization.

Role of VEGF Diffusion

VEGF is a protein that stimulates the formation of new blood vessels. In diabetic retinopathy, elevated levels of VEGF lead to abnormal growth of new blood vessels (neovascularization) in the retina, which can leak fluid and cause swelling, leading to vision loss.

The model uses finite-difference methods to simulate VEGF diffusion across the capillary grid, highlighting areas where ischemia is severe and where neovascularization might occur. This helps in understanding how these processes spread over time.

Importance of Blood Flow

Blood flow is crucial for maintaining retinal health as it delivers oxygen and nutrients to the retina while removing waste products. In diabetic retinopathy, impaired blood flow contributes significantly to tissue damage.

The model incorporates a Darcy pressure-driven blood-flow solution, which helps in visualizing how changes in capillary integrity affect overall blood circulation within the retina.

Frequently asked questions

Try it live

Everything above runs in your browser — open Diabetic Retinopathy: 2D Capillary Field & VEGF Diffusion Map and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.