Contributing factors for intraocular pressure control in patients with mostly normal-tension glaucoma after initial Ex-PRESS drainage device implantation

Abstract

Purpose: To investigate the postoperative intraocular pressure (IOP) control and identify the factors associated with failure of initial Ex-PRESS surgery in patients with open-angle glaucoma for 3 years.

Methods: A total of 79 patients with medically uncontrolled open-angle glaucoma (55 normal-tension glaucoma and 24 primary open-angle glaucoma) were enrolled. All patients underwent Ex-PRESS implantation (including combined cataract surgery). The outcome measure was the survival rate using life table analysis, the failure was defined as IOP of > 18 mmHg (criterion A), > 15 mmHg (criterion B) or > 12 mmHg (criterion C) and/or IOP reduction of < 20% from baseline (each criterion) without any glaucoma medications. The Cox proportional hazards model was used to identify risk factors for IOP management defined as the above criterion. RESULTS: The mean preoperative IOP was 19.3 ± 5.8 mmHg. At 36 months, the mean IOP was 11.8 ± 3.6 mmHg with a mean IOP change of 7.5 mmHg (reduction rate 39.0%). The cumulative probability of success was 58% (95%CI: 42-64%) (criterion A), 48% (95%CI: 37-59%) (criterion B) and 30% (95%CI: 20-40%) (criterion C). In multivariate analyses, factors that predicted poor IOP control included the intervention of bleb needling after 6 months after the surgery (HR: 2.43; 95%CI: 1.35-4.37; P = 0.032). Transient hypotony was observed in 4 patients.

Conclusion: The implementation of bleb needling after Ex-PRESS surgery in the late postoperative period was suggested to be the main risk factor for achieving lower IOP.

Keywords: Bleb needling; Ex-PRESS; Glaucoma surgery; Intraocular pressure; Primary open-angle glaucoma.