Numerical Study of Convection-Assisted Intra-Vitreous Drug Delivery in Human Eye

This study presents an in-vitro transient numerical simulation of the human eye to investigate the impact of vitreous convection on drug transport to the retinal surface. The convection of the fluid in a vitrectomized eye was simulated as a laser-induced spot heating of the retinal surface during intravitreal administration of medicines. The three-dimensional computational model was constructed using the physiological dimensions of the human eye. Drug transport was numerically simulated by solving suitable transient mass momentum and species conservation equations accounting for the natural convection flow of the VH. The vitreous body was modeled as a liquid. This is because, during retinal surgery, the gel-like vitreous humor is often replaced with Newtonian fluids. The natural vitreous humor also liquefies with age. The initial simulations unveiled a significant enhancement in dye concentration, reaching 13 mu g/mL at the central retinal pigmented epithelium (RPE) site within 10 min (0.16 h) with the application of convection-assisted diffusion. In contrast, achieving the same concentration through pure diffusion required a substantially prolonged period of 13.5 h. It is evident that convection hastens the arrival of drugs on the retinal surface, and this is beneficial for retina treatment under specific conditions.