Navigating hypotony challenges with XEN gel implantation

ABSTRACT

Introduction

The XEN Gel, a hydrophilic tube meticulously crafted to adhere to the principles of the Hagen – Poiseuille law, is designed to facilitate efficient aqueous shunting without inducing hypotony. Implantable ab interno or ab externo, with or without conjunctival opening, the device shows no significant outcome differences. Despite numerical hypotony signaling failure, patients may fare well below 6 mmHg.

Areas Covered

This review provides insights into device variability, challenges related to hypotony, associated risk factors, and hypotony management.

Expert opinion

The progressive evolution of the XEN Gel constitutes a significant advancement in the field of glaucoma management. Comparative studies investigating diverse implantation methodologies, particularly the ab interno and closed conjunctival approaches, highlight the device versatility in addressing individual patient needs. Exploring hypotony from both statistical and clinical perspectives challenges the traditional view of intraocular pressure as a straightforward success or failure indicator. The incidence of hypotony-related issues varies between device models, emphasizes the need for an individualized approach during device selection. Overall, understanding the dynamics of hypotony is crucial for optimizing the outcomes of XEN Gel implantation.

KEYWORDS:

• Ab interno
• choroidal detachment
• hypotony
• microShunt
• MIGS
• trabeculectomy
• XEN45 and XEN63
• XEN gel

Article highlights

• The incidence of clinical hypotony warrants more attention in both clinical management and research.

• A higher incidence of clinical hypotony was reported with XEN63 compared to XEN45.

• While hypotony is typically clinically evident through slit-lamp examination, detecting subclinical hypotony requires OCT. Furthermore, these changes may occur even with ‘normal’ IOP.

• Axial myopia stands out as the most significant risk factor for hypotony. However, further studies are necessary to identify high-risk groups and enhance clinical management.

• The two primary factors contributing to early postoperative hypotony are higher peritubular flow and lower episcleral outflow resistance, both of which decrease over time.

• Other factors influencing IOP have been described, including antimetabolite toxicity, and iatrogenic causes. Identifying such factors aids in planning the management of hypotony.

Declaration of interest

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.