Long Term Survival Of Functional Xen Stent Implant Adjacent To Previous Ahmed Valve Implants.

Presenting long term outcomes of 3 xen stent implants that where inserted adjacent to functioning Ahmed valve
implants in patients with primary open angle glaucoma.

 Reporting on 3 eyes of 2 patients who developed complete drop intolerance. All 3
eyes were pseudophakic with glaucoma controlled on a combination of an Ahmed valve and topical
drops. Due to severe drop intolerance drops the decision was made to insert Xen stent
implant in the upper quadrants away from the Ahmed valves.

The Ahmed valves had been in situ for over a year in all eyes. All cases have been
followed up for 5 years.

 All surgeries where performed by the same surgeon. Xen stents placements were in the upper quadrants away from the Ahmed valves i.e. if an Ahmed valve was situated supero temporally, the
Xen was placed supero nasally.

Xen stents were placed Ab interno with 0.1ml MMC (0.2mg/ml) subconjunctival injection in the superior fornix at the end of the procedure. Intracameral dexamethasone 0.4
mg as well as inferior subconjunctival dexametahsone 1mg were also administered at the end of the surgery.

All cases received 2 hourly steroid drops for 4 weeks, tapering over 4 weeks thereafter.
No cases required needling or additional sbconjunctival injections.

 At 5 year follow up, all 3 eyes maintained a formed bleb with IOP at or below target level (07mmHg, 10mmHg
and 10mmHg respectively).
Visual acuities remained excellent throughout (6/6, 6/6 and 6/5).
The visual fields showed 0.1dB decrease in 2 cases with no change in 1 eye with stable disc OCT images.
All 3 eyes remained drop free throughout the follow-up period.

The cases are presented to raise awareness of the long term success of ab interno bleb forming stents in
the presence of large seton implants.
The traditional dogma has always been that the limbal scarring caused by a seton implant will inevitable lead to bleb
forming procedure failure.
These blebs not only survived intact over a 5 year period but also did not require any post operative manipulation which
is usually needed in approximately 30% of Xen stent implantation procedures.