Effectiveness of Single-Digit IOP Targets on Decreasing Global and Localized Visual Field Progression After Filtration Surgery in Eyes With Progressive Normal-Tension Glaucoma

Abstract

Purpose: 

To examine the effectiveness of achieving single-digit intraocular pressure (IOP) targets with filtration surgery on decreasing global and localized visual field (VF) progression in eyes with progressive normal-tension glaucoma (NTG).

Methods: 

A retrospective chart review was conducted to identify NTG patients who underwent trabeculectomy with mitomycin C between 2006 and 2010 for progressive VF loss with preoperative IOP≤15 mm Hg during the 12 months before surgery. All eyes had glaucomatous optic neuropathy and progressive VF loss, uncontrolled IOP on maximum therapy, and a minimum of 2 baseline preoperative and 4 postoperative VF examinations. VF progression was assessed using Guided Progression Analysis (GPA) and Progressor software.

Results: 

Fifteen eyes of 14 patients (mean age 71.8±7.5 y) were enrolled with mean follow-up of 71±26 months. Mean postoperative IOP (8.5±3.5 mm Hg) was significantly (P<0.001) reduced compared with preoperatively (13.1±1.5 mm Hg). The probability of achieving an IOP goal ≤10 mm Hg was 66% at 4 years’ follow-up. The overall rate of postoperative VF progression using any method was 13.3% (1 eye using Progressor; 1 eye using GPA and Progressor). Average postoperative slope of MD (−0.25±0.86 dB/y) and pattern SD (0.49±0.83 dB/y) were improved (P=0.05 and 0.07) compared with the preoperative slopes (−1.05±0.66 and 1.21±0.71 dB/y).

Conclusions: 

Achieving single-digit IOP targets with filtration surgery has a beneficial effect on reducing global and localized rates of VF progression in NTG eyes with progression at low IOP.