Reduced Pulsatile Trabecular Meshwork Motion in Eyes With Normal Tension Glaucoma Using Phase-Sensitive Optical Coherence Tomography

Abstract

Purpose : To investigate whether the pulsatile trabecular meshwork (TM) motion change in normal tension glaucoma (NTG) comparing with normal and POAG using phase-sensitive optical coherence tomography (PhS-OCT).

Methods : In this cross-sectional study, 15 normal, 14 newly diagnosed NTG and 15 medication controlled POAG subjects were recruited. A laboratory-built PhS-OCT system was used to measure the TM motion. Two quadrants, temporal and nasal, were imaged and two parameters for pulsatile TM motion, maximum velocity (MV) and cumulative displacement (CD) were analyzed.

Results : Firstly, 15 normal, 14 NTG and 15 POAG eyes with mild visual field (VF) defect were compared. 1.2±1.8 medication was used in POAG eyes. Pulsatile TM motion in the temporal region were lower than that in the nasal region in all groups (p<0.01). Mean deviation (MD) was similar between NTG and POAG groups (p=0.773), as well as IOP among three groups (p=0.717). MV and CD in NTG were significantly lower than those in normal, whereas higher than POAG eyes (figure 1). Secondly, twelve subjects in both NTG and POAG groups presented asymmetric MD, one eye with mild while the other eye with severer VF defects (p<0.01). The MD and IOP was similar between eyes with different VF defects in NTG and POAG groups (p_MD=0.824, p_IOP=0.331). In NTG, MV and CD was roughly similar between eyes with different VF defects (p_NMV=0.350, P_NCD=0.287, p_TMV=0.043, P_TCD=0.590). However, in POAG group, MV and CD in eyes with mild defect was higher than that in severer eyes (p_NMV=0.01, P_{NCD, TMV, TCD}<0.01).

Conclusions : Pulsatile TM motion decrease in NTG. Besides TM biomechanical change, other factors involve NTG progression.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.