Safety and efficacy of achieving single-digit intraocular pressure targets with filtration surgery in eyes with progressive normal-tension glaucoma

Purpose: Whereas achieving intraocular pressure (IOP) targets ≤ 10mm Hg typically requires surgical intervention, we sought to examine the safety and efficacy of trabeculectomy in normal-tension glaucoma (NTG). Methods: Patients with progressive NTG undergoing trabeculectomy with preoperative IOP ≤15mm Hg during the 12-month period before surgery were identified at a single academic institution. Failure was defined as IOP reduction <20% below baseline (criteria A), <30% (criteria B), or <40% (criteria C), reoperation for glaucoma, or loss of light perception vision. Results: Thirty eyes of 28 patients (mean age, 73±8.7 y) were enrolled with a mean follow-up period of 50±31 months. Mean postoperative IOP (8.6±2.9mm Hg) and medications (0.6±1.0) at final follow-up was significantly (P<0.001) reduced compared with before surgery (13.2±1.4mm Hg and 2.5±1.2, respectively). The cumulative probability of failure during 5 years of follow-up was 32% (criteria A), 48%, (criteria B), and 67% (criteria C). The probability of successfully achieving an IOP goal ≤10mm Hg was 68% at 4 years of follow-up. Conclusions: Trabeculectomy is a safe and effective method for achieving single-digit IOP targets in NTG eyes with progression at low IOP.