Aqueous humor dynamics in human eye: A lattice Boltzmann study

Area of Science:

• Ophthalmology
• Biophysics
• Computational Fluid Dynamics

Background:

• Aqueous humor (AH) dynamics are crucial for maintaining intraocular pressure (IOP).
• Understanding AH flow, heat transfer, and outflow resistance is vital for diagnosing and treating glaucoma and other ocular conditions.
• Existing models may not fully capture the complex interplay of factors affecting AH dynamics.

Purpose of the Study:

• To develop and validate a lattice Boltzmann model for simulating aqueous humor dynamics in the human eye.
• To investigate the influence of various physiological and pathological factors on intraocular pressure.
• To provide a computational tool for studying ocular fluid dynamics.

Main Methods:

• Development of a lattice Boltzmann model incorporating incompressible Navier-Stokes flow, heat convection/diffusion, and Darcy seepage flow.
• Simulation of aqueous humor dynamics under different physiological conditions.
• Analysis of the impact of heat convection, buoyancy, AH production rate, trabecular meshwork permeability, AH viscosity, and anterior chamber angle on IOP.

Main Results:

• The model demonstrated stability, convergence, and robustness.
• Heat convection and diffusion significantly impact flow patterns in healthy eyes.
• Increased anterior chamber angle or decreased AH secretion rate, drainage resistance, and viscosity can control IOP.
• Pathologic eyes show greater sensitivity to these factors than healthy eyes.
• Temperature differences and eye orientation affect corneal and iris wall shear stresses.

Conclusions:

• The lattice Boltzmann model provides a reliable tool for simulating AH dynamics.
• Key factors influencing IOP have been identified, with implications for managing ocular conditions.
• The model offers a theoretical reference for future research in ocular fluid mechanics and disease.
• Viscosity of AH appears to have a limited direct impact on IOP regulation.