Age-related macular degeneration (AMD) is a leading cause of severe vision loss among the elderly population worldwide. Current treatment strategies rely on repeated intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents such as aflibercept and ranibizumab. To better understand the transport and efficacy of these drugs, we develop a three-dimensional pharmacodynamic model describing their distribution and interaction with VEGF in the eye.

We present a three-dimensional computational pharmacodynamic model that describes the transport, distribution, and therapeutic action of intravitreally administered anti-VEGF agents. The model consists of two coupled compartments representing the vitreous body and the retina. Drug transport in the vitreous is governed by a system of coupled convection–diffusion–reaction equations accounting for aqueous humor flow, molecular diffusion, and reversible binding kinetics. In the retina, diffusion–reaction equations describe drug penetration through the inner limiting membrane and subsequent interaction with VEGF. The model incorporates experimentally determined transport parameters and realistic ocular geometry.

The resulting system of partial differential equations is discretized in time using one-step θ-schemes and in space by the finite element method. Numerical simulations are performed to compare the pharmacodynamic behavior. Quantitative analyses include retinal drug exposure, VEGF suppression dynamics, and drug-specific treatment durability. Our simulations demonstrate that only a limited fraction of the injected drug reaches the retinal tissue due to the complex ocular physiology, including additional transport pathways and boundary conditions such as aqueous humor outflow through the Schlemm’s canal. Furthermore, the model predicts substantial differences in the duration of VEGF suppression between the two therapeutic agents.