XEN Gel Stent
The XEN Gel Stent bridges the gap between MIGS and traditional filtering surgery — a soft, minimally invasive implant that reaches lower target pressures by creating a new drainage pathway under the conjunctiva.
What Is the XEN Gel Stent?
The XEN Gel Stent is a minimally invasive glaucoma surgery (MIGS) device that works differently from the angle-based procedures. Rather than improving flow through the eye's natural drainage system, it creates an entirely new drainage route from inside the eye to the space beneath the conjunctiva — the same destination as a traditional trabeculectomy, but reached through a far less invasive approach. This makes the XEN a bridge between MIGS and conventional filtering surgery.
What Happens Anatomically During the Surgery
In filtering surgery, the goal is to let aqueous fluid escape the eye to a controlled reservoir under the conjunctiva (the thin, clear membrane covering the white of the eye), where it is reabsorbed. The XEN accomplishes this with a soft gelatin tube roughly six millimeters long.
Working from inside the eye (ab-interno), the surgeon uses a fine injector to pass the stent from the anterior chamber, through the sclera at the drainage angle, and out into the subconjunctival space. Once in place, the gelatin material hydrates and becomes soft and tissue-friendly. Aqueous now flows through the lumen of the tube to form a low, diffuse filtering bleb. An anti-scarring medication, mitomycin-C, is generally applied to keep the body from healing the new pathway closed.
Because it establishes subconjunctival drainage, the XEN can achieve a lower target eye pressure than the angle-based MIGS devices, while avoiding the larger dissection of a full trabeculectomy.
Which Types of Glaucoma It Helps
The XEN is used for open-angle glaucoma, including cases that are more advanced or that need a lower target pressure than an angle-based MIGS can reliably deliver, and for glaucoma that has not been controlled by drops or laser. It can be a good option when a patient needs stronger pressure reduction but a surgeon wants to avoid, or delay, a full trabeculectomy. It can be performed on its own or combined with cataract surgery. As with filtering surgery generally, it is not the first choice for a purely angle-closure mechanism without addressing the angle.
Benefits
The XEN Gel Stent offers a valuable middle ground in the glaucoma toolkit:
- ✓Reaches lower target pressures than angle-based MIGS, closer to what filtering surgery achieves
- ✓Placed from inside the eye with far less tissue disruption than a traditional trabeculectomy
- ✓Soft, flexible, biocompatible material designed to be gentle on surrounding tissue
- ✓Can be performed alone or combined with cataract surgery
- ✓A reasonable step before committing to a full trabeculectomy or tube shunt in appropriate patients
Risks & Considerations
Because the XEN creates a filtering bleb, it shares some of the considerations of traditional filtering surgery, to a lesser degree. Eye pressure can occasionally drop too low in the early period (hypotony), the bleb can scar down and reduce the stent's effect over time, and a minority of patients need a bleb "needling" revision in the office to restore flow. As with any bleb, there is a small long-term risk of leakage or infection (blebitis) that makes ongoing monitoring important. Other possible issues include a temporary pressure rise, minor bleeding, or stent malposition. Compared with angle-based MIGS, the XEN trades a somewhat higher monitoring burden for the ability to reach a lower pressure.
The XEN Gel Stent is one of several MIGS options and sits at the more powerful end of the spectrum. For how it compares with the iStent, goniotomy, and canaloplasty, see our MIGS Surgery page. When even greater pressure reduction is needed, see our Trabeculectomy and Tube Shunt Surgery pages.
Frequently Asked Questions
What is the XEN Gel Stent?
The XEN Gel Stent is a soft, flexible tube about the length of an eyelash, made from a gelatin material that becomes pliable in the eye. It is placed from inside the eye to create a new drainage channel from the anterior chamber to the space under the conjunctiva, forming a small filtering bleb.
How is the XEN different from an iStent or canaloplasty?
Angle-based MIGS such as the iStent, goniotomy, and canaloplasty work within the eye's existing drainage system and produce a modest pressure reduction. The XEN instead bypasses that system entirely and drains to the subconjunctival space, like a trabeculectomy, so it can reach a lower target pressure &mdash but with some of the bleb-related monitoring that filtering surgery involves.
Does the XEN require a bleb?
Yes. Because the XEN drains fluid to the subconjunctival space, it forms a small filtering bleb (a fluid reservoir under the conjunctiva). This is what allows a lower pressure, but it also means the bleb needs monitoring, and an anti-scarring medication (mitomycin-C) is typically used to keep it working.
Can the XEN be combined with cataract surgery?
Yes. The XEN Gel Stent can be implanted on its own or at the same time as cataract surgery, depending on your needs.
See a glaucoma specialist. Dr. Robert Gunzenhauser is Harvard-educated and UCLA fellowship-trained in glaucoma, providing expert diagnosis and treatment for XEN Gel Stent at Inland Glaucoma Center in Upland, CA.