Long-Term Functional Outcomes of Glaucoma Tube Shunt Revision Surgery

The Success Rate of Glaucoma Drainage Device Revision

PRCIS

We report the survival of surgical revision to glaucoma drainage devices for several indications in a large cohort of patients, with an overall success rate of 45% at 36 months.

PURPOSE

To evaluate the outcomes of surgical revision for complications of glaucoma drainage devices.

METHODS

Three hundred thirty-five eyes of 318 patients who underwent tube revision or removal at University of California Los Angeles (UCLA) Jules Stein Eye Institute between 1997 and 2019 were included. The pre-defined primary outcome measure was surgical success of the initial revision, defined as resolution of the condition with no additional revisions required, no functionally significant change in vision, and no instances of intraocular pressure > 21 mmHg at 2 consecutive visits postoperatively. Kaplan-Meier survival analysis was applied to evaluate survival at 36 months based on these criteria. The Wilcoxon paired test was used to compare mean preoperative and postoperative intraocular pressure, medication usage, and visual acuity.

RESULTS

Overall, survival of revised tubes at 36 months was 45%. The 4 most common indications for revision were exposure of the implant (42% of all revisions), occlusion (14%), corneal failure or threat of failure (12%), and hypotony (11%). Survival at 36 months for each of these indications was 44%, 45%, 52%, and 37%, respectively.

CONCLUSIONS

These results suggest that eyes with glaucomatous damage with long-term glaucoma drainage device complications can still have a reasonably successful outcome when a revision is performed. However, with substantial rates of vision loss and a frequent need for additional revisions to manage complications, managing patient expectations for success and making them aware of the likelihood of additional surgeries or failure is important.

Effect of immediate shallow anterior chamber after Ahmed glaucoma valve implantation on intermediate-term intraocular pressure control

Purpose:

To evaluate the incidence of shallow anterior chamber in the early postoperative period following Ahmed glaucoma valve (AGV) implantation and its effect on the hypertensive phase (HP), intermediate-term intraocular pressure (IOP) control, and success rate.

Methods:

A retrospective analysis of 369 eyes of 360 patients who underwent AGV implantation between January 2005 and January 2020 with a minimum follow-up of 2 months was performed. Twenty-six patients developed shallow anterior chamber (AC) within 8 weeks following surgery (cases). They were compared with 39 randomly selected controls (no shallow AC post AGV). HP (IOP spike >21 mmHg), use of ocular hypotensive medications, and other associations were compared.

Results:

Incidence of shallow AC post AGV was 7% (95% confidence interval [CI] 4, 9). The onset of shallow AC was 3 ± 2.1 days and resolved within 6 ± 4.7 days. Hypotony (12 [47%] vs. 1 [2.5%], P 0.0001) and choroidal detachment (CD; 7 [27%] vs. 3 [8%], P 0.03) were more common in cases compared to controls. The HP occurred in 11 (43%) cases versus 13 (34%) controls (P 0.4). Cases required more ocular hypotensive medications than controls at the end of 8 weeks (1.1 ± 1 vs. 0.5 ± 0.5, P 0.01). There was no significant difference in the qualified success between the groups at 1 year.

Conclusion:

The development of postoperative shallow AC post AGV implantation was not detrimental to IOP control at 1 year. However, there is a need to monitor the occurrence of HP in these eyes.

Tube Length Adjustment and Tube Trimming Technique in Refractory Glaucoma

Secondary glaucoma may develop after vitreoretinal surgery as it is a known risk factor for its development. When the risk factors are more than one, for instance along with neovascular glaucoma (NVG), the secondary glaucoma may become recalcitrant and very difficult to manage. Surgical intervention is often warranted to control intraocular pressure (IOP) and prevent progressive glaucomatous damage in patients with refractory glaucoma, and glaucoma drainage implant may be preferred as the primary choice. We describe a patient who develop secondary glaucoma after vitrectomy and silicone oil (SO) injection due to unresolved vitreous hemorrhage in proliferative diabetic retinopathy (PDR) and subsequent NVG. Baerveldt glaucoma implant (BGI) was carried out and placed in the superotemporal quadrant with longer anterior chamber tube placement to prevent escape of SO through the tube. Qualified success was achieved with additional one fixed-drug combination (FDC). However, 3 years later, the tube was blocked by the iris tissue at the inferior edge of the pupil. Tube trimming was performed efficiently using a simple technique. The distal end of the tube was pulled out of the anterior chamber through a paracentesis just next to the tube entrance and trimmed to the appropriate length. More than a year after the surgery, IOP was still well controlled with the same FDC. Unfortunately, the visual acuity could not be recovered due to advanced PDR.