Early Postoperative Aqueous Suppression Therapy and Surgical Outcomes of Ahmed Tube Shunts in Refractory Glaucoma

Purpose: To compare early vs. delayed use of aqueous suppressants on Ahmed glaucoma valve (AGV) outcomes.

Design: Single-center retrospective comparative case series.

Participants: Patients who underwent AGV surgery at Wills Eye Hospital in the period between 2016 and 2021.

Methods: Retrospective review of AGV surgery at Wills Eye Hospital 2016 to 2021 for refractory glaucoma. Two groups were created: group 1 or those who received early aqueous suppressant therapy in the first 2 weeks postoperatively whenever the intraocular pressure (IOP) was > 10 mmHg, and group 2 or those who received delayed treatment after 2 weeks whenever the IOP exceeded the target pressure. Aqueous suppressant therapy included topical beta blockers, carbonic anhydrase inhibitors, and/or alpha agonists.

Main outcome measures: The primary outcome measures were the frequency of hypertensive phase (HP) defined as IOP > 21 mmHg in first 3 months after an initial reduction to 21 mmHg or less in the first postoperative week not caused by tube obstruction or retraction, and month-12 surgical failure defined as 5 ≥ IOP > 21 mmHg on 2 consecutive visits, vision decline to no light perception (NLP), or glaucoma reoperation. Secondary outcome measures included changes in visual acuity (VA), IOP, and glaucoma medications at 12 months. Predictive factors for surgical failure were also identified.

Results: A total of 407 eyes of 391 patients (260 in group 1, 147 in group 2) with similar baseline characteristics were included. Hypertensive phase was more common in group 2 than 1 (41.5% vs. 18.5%; P < 0.001). At month 12 (N = 303 eyes), group 1 was less likely to fail than group 2 (21.2% vs. 36.8%, P = 0.003). Multivariate regression analysis showed that HP (odds ratio [OR] = 10.47, P < 0.001), delayed aqueous suppression use (OR = 2.17, P = 0.003), and lower baseline VA (OR = 1.56, P = 0.015) were the strongest predictors of month-12 failure.

Conclusions: Early use of aqueous suppressants may lower the risk of HP and improve AGV outcomes.

Financial disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.