Evaluation of the Ultrastructural and In Vitro Flow Properties of the PRESERFLO MicroShunt



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Ibarz Barberá, Marta and Hernández Verdejo, José Luis and Bragard, Jean and Burguete, Javier and Morales Fernández, Laura and Tañá Rivero, Pedro and Gómez de Liaño, Rosario and Teus Guezala, Miguel Ángel (2021) Evaluation of the Ultrastructural and In Vitro Flow Properties of the PRESERFLO MicroShunt. Translational vision science & technology, 10 (13). 10 p.. ISSN 2164-2591

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Official URL: https://doi.org/10.1167/tvst.10.13.26


Purpose: To measure the in vitro flow properties of the PRESERFLO implant for comparison with the theoretical resistance to flow.
Methods: The PRESERFLO was designed to control the flow of aqueous humor according to the Hagen-Poiseuille (HP) equation. Scanning electron microscopy (SEM) was performed to analyze the ultrastructure, and flowmeasurementswere carried out using a gravity-flow setup.
Results: SEM images of the PRESERFLO showed luminal diameters of 67.73 × 65.95 μm and 63.66 × 70.54 μm. The total diameter was 337.2 μm, and the wall was 154 μm wide. The theoretical calculation of the resistance to flow(R) for an aqueous humor (AH) viscosity of 0.7185 centipoises (cP) was 1.3 mm Hg/(μL/min). Hence, assuming a constant AH flow of 2 μL/min, the pressure differential across the device (�P) was estimated to be 2.6 mm Hg. The gravity-flow experiment allowed us to measure the experimental resistance to flow, which was RE =1.301mmHg/(μL/min), in agreement with the theoretical resistance to flow R given by the HP equation.
Conclusions: The experimental and theoretical flow testing showed that the pressure drop across this device would not be large enough to avoid hypotony unless the resistance to outflowof the sub-Tenon space was sufficient to control the intraocular pressure in the early postoperative period.
Translational Relevance: The fluid properties of glaucoma subconjunctival drainage devices determine their specific bleb-forming capacity and ability to avoid hypotony and therefore their safety and efficacy profile.

Item Type:Article
Additional Information:

Received: August 24, 2021 / Accepted: October 21, 2021 / Published: November 18, 2021.

Uncontrolled Keywords:PRESERFLO; aqueous flow; pressure drop; glaucoma surgery; Hagen-Poiseuille
Subjects:Medical sciences > Medicine > Surgery
Medical sciences > Medicine > Ophtalmology
ID Code:68964
Deposited On:24 Feb 2022 14:12
Last Modified:25 Feb 2022 09:08

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