Optic nerve pulsatile deformation in open angle glaucoma after intraocular pressure manipulation measured by OCT

Abstract

Objective: To investigate the effect of intraocular pressure (IOP) decrease on pulsatile displacement in the optic nerve head (ONH) of primary open angle glaucoma (POAG) patients with and without axial myopia. Methods: Twenty-eight POAG patients (19 without myopia and 9 with axial myopia) were included in the study. We obtained OCT videos from participants with diagnosis of primary open angle glaucoma (POAG), treated with medical or surgical treatment, with a minimum IOP drop of 4 mmHg. After rigid registration, an algorithm based on non-rigid registration was applied to measure maps of local pulsatile displacement in the ONH based on high-frequency OCT imaging. Results: In the non-myopic glaucoma cohort, there was a 13.7% decrease in pulsatile displacement after the intervention compared to the baseline (p=0.03). In contrast, the glaucoma patients with axial myopia showed no statistically significant change. Furthermore, there was no significant association between pulsatile displacement and age, sex, IOP change, or glaucoma severity. However, there was a positive correlation between the absolute displacement change and the absolute change in the anterior prelaminar tissue depth before and after intervention (R2=0.1 p= 0.03, CI [0.0009-0.02]). No significant correlation was found between any of the OCT and visual field parameters and the pulsatile displacement in any of the cohorts. Conclusion: In POAG patients without myopia, IOP decrease led to a significant reduction in pulsatile displacement in the ONH. The pulsatile displacement increase compared to baseline was positively correlated with the reduction in the anterior prelaminar tissue depth, suggesting that this parameter may play a role in ONH biomechanics. These findings may have implications for understanding the pathophysiology of POAG and developing new treatment strategies.