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  • Glaucoma

    Review of: Early postoperative aqueous suppression therapy and surgical outcomes of Ahmed tube shunts in refractory glaucoma

    Shalaby W, Wong J-C, Zhang T, et al. Ophthalmology Glaucoma, January/February 2024

    In the 3 months following valved tube shunt surgery, some patients may experience a dramatic rise in IOP, otherwise known as the hypertensive phase (HP). The authors hypothesized that introducing aqueous suppressant therapy soon after surgery may reduce the incidence of HP, improve surgical outcomes, and lower the risk of surgical failure at month 12.

    Study Design

    This was a single-center, retrospective comparative case series that included 391 patients (407 eyes) who underwent Ahmed glaucoma valve (AGV) implantation for refractory glaucoma between 2016 and 2021. Patients were divided into 2 groups based on the timing of postoperative aqueous suppressant therapy initiation: early treatment within the first 2 weeks when IOP was >10 mm Hg (Group 1) or delayed treatment after 2 weeks when IOP exceeded the target pressure (Group 2). The primary outcome measures were the incidence of HP within the first 3 months after surgery and surgical failure at 12 months.


    Group 1 had a significantly lower incidence of HP than Group 2 (18.5% vs 41.5%, respectively) as well as a lower month 12 surgical failure rate (21.2% vs 36.8%, respectively). A multivariate regression analysis found that the strongest predictors of month 12 surgical failure were HP, delayed aqueous suppression, and lower baseline visual acuity.


    The study's retrospective design might have introduced bias, as there was no defined protocol as to when treatment was started. Additionally, there were no predefined standards for adding medications, and each surgeon may have had different thresholds for recommending additional therapy.

    Clinical Significance

    The results of the study suggest that initiating early aqueous suppressant therapy within the first 2 weeks following AGV implantation significantly reduces the incidence of HP compared with waiting until after 2 weeks. The HP is a common complication after valved tube shunt surgery and can lead to uncontrolled IOP requiring additional interventions. By attenuating the inflammatory processes underlying the HP, early aqueous suppression therapy may improve surgical outcomes and reduce the risk of surgical failure at month 12. Ophthalmologists may use these findings to consider early initiation of aqueous suppressants following AGV surgery to optimize patient outcomes.

    Financial disclosures: Dr. Lilian Nguyen discloses financial relationships with AbbVie (Consultant/Advisor).