Intraoperative OCT-Guided Repositioning of the Preserflo MicroShunt

Abstract

Purpose To evaluate the utility of intraoperative optical coherence tomography (iOCT) in guiding the optimal positioning of the Preserflo MicroShunt (PMS) during glaucoma surgery, with the aim of preserving endothelial cell density (ECD) and improving postoperative outcomes.

Patients and Methods This case series includes three patients who underwent PMS repositioning due to tube-endothelium (T-E) contact identified on the anterior segment OCT (AS-OCT). Reoperations were performed using microscope-integrated iOCT to guide and verify the intraoperative position of the implant. Final T-E distance was confirmed postoperatively with AS-OCT.

Results In all cases, AS-OCT revealed T-E contact with associated epithelial ingrowth, prompting surgical repositioning of the PMS. iOCT provided real-time visualisation during surgery, enabling accurate adjustment of tube positioning and increased T-E separation. Postoperative assessments demonstrated stable or minimally reduced ECD; intraocular pressure was effectively controlled without topical therapy, and corneal transparency was preserved in all patients.

Conclusions iOCT is a valuable tool in PMS implantation, allowing real-time assessment and optimisation of tube positioning. Ensuring adequate T-E distance minimises endothelial trauma and reduces the risk of long-term ECD loss. Routine use of iOCT during primary implantation may enhance surgical precision and reduce the need for reinterventions.

Zusammenfassung

Ziel Bewertung des Nutzens der intraoperativen optischen Kohärenztomografie (iOCT) zur Unterstützung der optimalen Positionierung des Preserflo MicroShunt (PMS) während der Glaukomchirurgie mit dem Ziel, die endotheliale Zelldichte (ECD) zu erhalten und postoperative Ergebnisse zu verbessern.

Patienten und Methoden Diese Fallserie umfasst 3 Patienten, bei denen eine Repositionierung des PMS aufgrund eines Kontakts zwischen dem Drainagerohr und dem Hornhautendothel (T-E-Kontakt), nachgewiesen durch eine vordere OCT (AS-OCT), erforderlich war. Die Reoperationen wurden unter Verwendung eines in das Operationsmikroskop integrierten iOCT durchgeführt, um die Lage des Implantats intraoperativ zu steuern und zu bestätigen. Der endgültige T-E-Abstand wurde postoperativ mittels AS-OCT überprüft.

Ergebnisse In allen Fällen bestätigte die AS-OCT einen Kontakt zwischen dem PMS und dem Hornhautendothel, was eine chirurgische Repositionierung erforderlich machte. Die iOCT ermöglichte eine Echtzeitvisualisierung während der Operation, wodurch eine präzise Anpassung der Tubuslage und ein vergrößerter T-E-Abstand erzielt wurden. Postoperative Kontrollen zeigten eine stabile oder nur geringfügig reduzierte ECD, der Augeninnendruck (IOP) war ohne lokale Therapie gut kontrolliert, und die Hornhauttransparenz blieb erhalten.

Schlussfolgerungen Die iOCT ist ein wertvolles Hilfsmittel bei der Implantation des PMS, da sie eine intraoperative Echtzeitbewertung und Optimierung der Tubuspositionierung ermöglicht. Ein ausreichender T-E-Abstand minimiert das Risiko endothelialer Schäden und könnte den langfristigen Zellverlust begrenzen. Der routinemäßige Einsatz von iOCT bei der Primärimplantation könnte die chirurgische Präzision erhöhen und die Notwendigkeit späterer Reoperationen reduzieren.

Conclusion Box

Already known:

• The Preserflo MicroShunt (PMS) is a minimally invasive bleb-forming device for glaucoma surgery that has demonstrated favorable safety and efficacy profiles.

• Endothelial cell loss is a known complication of intraocular implants, and shorter tube-to-endothelium (T-E) distances are associated with greater endothelial damage.

• While anterior segment OCT can assess T-E distance postoperatively, intraoperative methods to optimize tube positioning remain underutilized and poorly studied.

Newly described:

• This case series demonstrates that intraoperative OCT (iOCT) enables real-time visualization of PMS tube position and facilitates precise surgical repositioning.

• The use of iOCT during surgery allowed for immediate correction of suboptimal tube positioning and improved postoperative tube-endothelium separation.

• Our findings suggest that integrating iOCT into PMS implantation may enhance intraoperative decision-making and help minimize endothelial damage, though further studies are needed to confirm these benefits.

Keywords

glaucoma - cornea - conjunctiva

Schlüsselwörter

Glaukom - Kornea - Bindehaut

Publication History

Received: 25 May 2025

Accepted: 20 August 2025

Accepted Manuscript online:
22 August 2025

Article published online:
17 October 2025

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