PATIENT-SPECIFIC VIRTUAL SIMULATOR OF TISSUE PERFUSION IN THE LAMINA CRIBROSA

Abstract

Purpose : Improper perfusion of the lamina cribrosa (LC) may lead to severe alterations of the visual function.
LC perfusion parameters are difficult to estimate with non-invasive measurements and are affected by many factors that vary among individuals and cannot be easily isolated. Here we utilize a mathematical virtual simulator (MVS) to address these challenges.

Methods : The MVS combines i) a three-dimensional porous-media model for LC perfusion with ii) a circuit-based model for blood flow in the retrobulbar and ocular posterior segments (Fig. 1).
Systems i) and ii) are solved using advanced computational and visualization methods (Feel++).
Simulation inputs may include some patient-specific factors that can be measured non-invasively, e.g. systolic blood pressure (SBP), diastolic blood pressure (DBP), intraocular pressure (IOP) and ocular geometry.

Results : Fig. 2a shows the MVS visualization of ocular geometry.
MVS simulated LC perfusion velocities at time t = 2.4 s (green line) are shown for IOP = 15 mmHg and SBP/DBP = 100/70 mmHg (Fig. 2b), SBP/DBP = 120/80 mmHg (Fig. 2c), SBP/DBP = 140/90 mmHg (Fig. 2d).
Increasing SBP and DBP leads to higher LC perfusion velocities, especially near the nasal area.
MVS also simulates blood velocities in the central retinal artery and vein (CRA and CRV), as shown in Figs. 2e and 2f, respectively, which are similar to those obtained via direct Imaging modalities.

Conclusions : MVS may serve as an instrument to illustrate and estimate LC perfusion parameters and predict their spatial variability, thereby providing new means to address the increasing demand of information on parts of the eye that are not-easily accessible with standard investigation instruments.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Figure 1: MVS multiscale scheme

 

Figure 2: MVS perfusion simulations