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WGC-2021

Abstract #84916 Published in IGR 21-1

The effects of negative periocular pressure on intraocular pressure

Ethier CR; Yoo P; Berdahl JP
Experimental Eye Research 2020; 191: 107928

See also comment(s) by Arthur Sit


Glaucoma is a major cause of blindness, and IOP reduction remains the only clinically-validated therapy. In this study, we analyze a novel IOP-lowering strategy that uses a modest negative pressure (vacuum) applied locally to the periorbital region by a pair of goggles with each lens individually connected to a programmable pump. Motivated by clinical data showing an IOP reduction, we used an existing validated lumped-parameter model of the eye to understand the putative mechanism of this treatment. The model considers aqueous humor dynamics, episcleral venous pressure, and changes in ocular blood volume to describe how IOP changes with time in response to an external perturbation. We find that clinical data are qualitatively and quantitatively consistent with model predictions if we include two primary mechanisms in the model: first, negative pressure application causes a relatively rapid increase in globe volume accompanied by increased blood volume in the eye. Second, negative pressure application reduces episcleral venous pressure, causing a slower adjustment of IOP due to altered aqueous humor dynamics. These results provide testable hypotheses that hopefully will lead to a fuller experimentally-driven understanding of how negative periocular pressure influences IOP. Evaluating the long-term effects of such treatments on glaucoma patients requires further clinical study.

Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA. Electronic address: ross.ethier@bme.gatech.edu.

Full article

Classification:

6.1.3 Factors affecting IOP (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)
9.4.9 Glaucomas associated with elevated episcleral venous pressure (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)



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