XEN Gel Stent Bleb Survives Longest With Ab-Externo Approach

Glaucooma check
The implantation approach has similar success as ab-interno, without a significant difference in the rate of complications.

This article is part of Ophthalmology Advisor’s conference coverage from the 2021 meeting of American Society of Cataract and Refractive Surgery (ASCRS), held in Las Vegas from July 23 to 27, 2021. The team at Ophthalmology Advisor will be reporting on a variety of research presented by the cataract and refractive surgery experts at ASCRS. Check back for more from the ASCRS 2021 Meeting.


During XEN® Gel Stent (AqueSys, Inc.) implantation, an ab-externo approach resulted in bleb survival of nearly twice as long compared with an ab-interno approach. These findings were presented during the American Society of Cataract and Refractive Surgery (ASCRS) annual meeting held July 23-27, 2021, in Las Vegas, Nevada.

Eyes (N=72) that underwent primary open-angle glaucoma surgery with XEN gel stent implantation were assessed in this study. An ab-interno approach was used for 39 eyes and ab-externo approach for 33 eyes. Surgical success at 6 months, as defined by intraocular pressure ≤15 mm Hg and ≥25% reduction from baseline of intraocular pressure (IOP) or medication without vision-threatening complications, were compared between surgical approaches.

The rate of surgical success was 59.0% for ab-interno and 42.4% for ab-externo approaches (P =.16).

The average IOP was 15.5 mm Hg and 16.0 mm Hg at 6 months for the ab-interno and ab-externo cohorts (P =.678), respectively. Compared with baseline, the average IOP was reduced by 41.0% among the ab-interno patients and 19.4% among the ab-externo approaches (P =.08).

At 6 months, patients in the ab-interno cohort had reduced medication by an average of 2.00 to 1.1 and the ab-externo cohort reduced medication by 1.5 to 1.5 (both P ≥.197).

Needling was required for blebs among 48.7% of ab-interno and 39.4% of ab-externo procedures (P =.428). The mean time to needling was shorter for the ab-interno approach procedures (28.6 vs 53.6 days; P =.036). Bleb failure was observed among 53.8% and 48.6% for the ab-interno and ab-externo approaches (P =.783), respectively.

The study authors concluded that both ab-interno and ab-externo approaches for XEN gel stent implantation among patients with open-angle glaucoma resulted in similar outcomes with the exception that blebs after an ab-externo approach survived nearly twice as long as blebs after an ab-interno surgical approach.

Disclosure: One study author declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  

Visit Ophthalmology Advisor’s conference section for complete coverage of the ASCRS 2021 meeting and more.



Nguyen V, An J. Xen gel stent implantation in primary open-angle glaucoma patients: comparison of surgical approaches. Presented at: 2021 ASCRS Annual Meeting; July 23-27, 2021; Las Vegas, NV. Poster 78122.