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Editors Selection IGR 12-2

Surgical Treatment: XEN-45 Gel stent implantation is effective and safe

Comment by Shan Lin & Sunee Chansangpetch on:

The Xen Gel Stent is a minimally invasive subconjunctival drainage implant for glaucoma, proven effective in primary open-angle glaucoma (POAG) and increasingly used in other glaucoma types such as primary angle-closure glaucoma (PACG) and secondary glaucoma. As a result, the use of the Xen Gel Stent has recently expanded to include various types of glaucoma, such as pseudophakic angle-closure and secondary glaucoma. Surgical techniques have also evolved from ab interno to more widely adopted ab externo approaches. However, few studies have directly compared Xen outcomes across different glaucoma types and surgical approaches.

In this prospective observational study, Kuankuan et al. reported 1-year outcomes of the Xen-45 Gel Stent in 48 Chinese eyes. The cohort included patients with three glaucoma diagnoses: POAG, pseudophakic PACG, and secondary glaucoma. The study showed a significant reduction in intraocular pressure (IOP), from 20.5 to 13.5 mmHg, and a decrease in the number of medications from 3 to 0. Success rates were 91.3% (qualified success) and 73.9% (complete success), in line with a prior meta-analysis (74.0%-89.2%).¹ The IOP, number of medications, and visual acuity outcomes were equivalent across the three diagnosis types. These findings are consistent with Sng et al., who reported no difference in IOP reduction between POAG and PACG eyes,² and with Schargus et al., who found similar outcomes between POAG and secondary glaucoma.³ Eyes that underwent the ab interno approach had significantly higher IOP at 1 month postoperatively compared to those treated with ab externo approaches.

A notable finding was the relatively high needling rate of 56.3%. Although no significant risk factors—including glaucoma subtype or surgical technique—were identified, needling appeared more frequent in the ab interno group (71%) than in the transconjunctival (48%) and open conjunctiva (60%) ab externo groups. This high rate may be attributable to the inclusion of eyes with previous glaucoma surgery or to ethnic differences, as all participants in this study were Chinese. Supporting this, Tan et al. found that Asian ethnicity was associated with a higher risk of not achieving complete success.⁴

In terms of safety, the most common complication reported was shallow anterior chamber (12.5%), followed by transient hypotony (6.3%) and tube obstruction (6.3%). In contrast, a meta-analysis of Xen implants reported rates of shallow anterior chamber and lumen obstruction to be less than 1%.¹ The higher rates observed in this study may be attributed to anatomical differences in the Chinese eyes.

Limitations included a small sample size, particularly in the pseudophakic PACG group, potentially affecting statistical power. Despite this, the study provides valuable data on the efficacy and safety of the Xen-45 Gel Stent in a Chinese population. As surgical outcomes may differ across ethnic groups, this dataset offers important insights into ethnic-specific outcomes. The results also suggest broader applicability of the device beyond POAG, with a comparison of three surgical techniques revealing a slight trend toward higher needling rates with the ab interno approach.

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