Optic nerve pulsatile displacement in open angle glaucoma after intraocular pressure manipulation measured by optical coherence tomography

Author Block: Marisse Masis Solano¹, Emmanuelle Richer², Santiago Costantino¹, Mark R. Lesk¹. ¹Universite de Montreal, ²Polytechnique de Montreal.

Author Disclosures: M. Masis Solano: None. E. Richer: None. S. Costantino: Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); CIHR, CSA. M.R. Lesk: Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); CIHR, CSA.


Abstract Body: 

Purpose: To apply a non-invasive optical coherence tomography (OCT) based technique to quantitatively assess the pulsatile displacement of the optic nerve head (ONH) tissue in glaucoma patients before and after lowering intraocular pressure (IOP) 

Study Design: Cohort study 

Methods: Participants with diagnosis of primary open angle glaucoma (POAG), treated with medical or surgical therapy with a minimum IOP drop of 5mmHg. Application of a simple algorithm to measure maps of local pulsatile displacement in the ONH based on high-frequency swept-source OCT imaging. Displacement was measured in a cohort of 12 participants before and after IOP lowering (both medical and surgical intervention). Intraocular pressure was measured by dynamic contour tonometry (Pascal). 

Results: Participants with POAG diagnosis (5 mild and 7 advanced) were imaged before and after intervention. Treatment modality was determined by standard medical care. Subjects with moderate glaucoma were treated medically and surgery was performed in advanced cases. Mean age was 68±4years. Mean IOP drop was 5.79mmHg. Before intervention
there was a median pulsatile displacement of neuroretinal rim tissue of 6.02±1.2μm compared to a displacement of 4.76±1.4μm after IOP decrease (p<0.005). Therefore, there was a 20% decrease in pulsatile displacement after intervention. Multivariate analysis showed no significant correlation with age, sex, disease stage or absolute IOP change for this cohort. 

Conclusions: Our non-invasive and clinically available method demonstrates a decrease in the ONH tissue pulsatility after IOP lowering. This imaging paradigm could lead to a better understanding of the biomechanical and vascular response of the ONH to glaucoma therapy. Further research is required to replicate the results but the clinical applications of our novel method show great translational promise.

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