Intraocular Pressure Equations Utilizing Aqueous Fluid Flow and Flow Facility in the Steady-State and Time-Dependent Domains.

PURPOSE

Enhanced understanding of intraocular pressure (IOP) dynamics by developing models improving upon foundational work in both steady-state and time-dependent domains.

METHODS

Two novel base equations are developed describing IOP dependent upon aqueous fluid flow into and out of the eye. The equations incorporate the parameters of fluid facility, venous and arteriolar pressures as well as initial and steady-state IOP. Basic validation was completed replicating existing glaucoma interventional studies. Equation 1 is a steady-state approximation of equilibrium between linear inflow and outflow facilities whose intercepts are the arteriolar intercept pressure and venous pressure, respectively. Equation 2 is a time-dependent approximation of IOP from an initial IOP also incorporating two or more inflow and outflow facilities as well as the steady-state solution.

RESULTS

The steady-state equation was validated by replicating the results of a published IOP efficacy study of combined netarsudil and latanoprost treatment results with a 3% error. The time-dependent equation was validated by replicating a published study examining mean time response of latanoprost IOP reduction to steady-state with an 8% error.

DISCUSSION

The combined steady-state and time-dependent IOP equations enable IOP equilibrium modeling incorporating inflow and outflow facility and the effects of arteriolar and venous pressures. Validation demonstrates applicability of the model with added interventional outflow and time-dependent IOP responses. Enhanced IOP equations provide a novel framework for modeling IOP dynamics. Potential applications include understanding IOP pathophysiology, evaluating therapeutic interventions, and predicting temporal/diurnal IOP fluctuations.