Modeling the relation between intraocular pressure and human trabecular meshwork fluid-mechanical properties

Area of Science:

• Ophthalmology
• Biophysics
• Fluid Mechanics

Background:

• Elevated intraocular pressure (IOP) is a primary risk factor for primary open angle glaucoma (POAG), a leading cause of blindness.
• The trabecular meshwork (TM) regulates aqueous humor (AH) outflow, making its properties crucial for maintaining normal IOP.

Purpose of the Study:

• To investigate the relationship between increased IOP and the fluid-mechanical properties of the TM.
• To model the TM as a deformable biphasic porous medium and analyze its hydraulic resistance.

Main Methods:

• Representing the TM as an axisymmetric deformable biphasic porous medium with pressure-dependent hydraulic permeability.
• Solving Darcy's law to determine TM hydraulic resistance (TMR) based on radial pressure drop.
• Incorporating TM stiffness using a shape function derived from human eye outflow facility measurements.
• Simulating AH flow using an electric equivalent scheme of the eye.

Main Results:

• TM hydraulic resistance (TMR) was found to increase with TM stiffness.
• Simulations showed a progressive increase in IOP as TMR rises, exceeding normal physiological limits.
• The study highlights the impact of microscopic TM properties on overall ocular function.

Conclusions:

• Trabecular meshwork stiffness significantly influences hydraulic resistance and intraocular pressure.
• Mathematical modeling and experimental data integration are essential for understanding POAG.
• Findings support the development of patient-specific therapies for POAG by considering individual TM characteristics.