Effectiveness of Trabeculectomy in Primary Open-Angle Glaucoma with Low Preoperative Intraocular Pressure

Purpose: The aim of this study was to evaluate the efficacy of trabeculectomy for primary open angle glaucoma (POAG) with low preoperative intraocular pressure (IOP). Patients and Methods: This was a retrospective single facility, non-randomized study. We included POAG patients with preoperative IOP ≤12 mmHg who were taking maximally tolerance glaucoma medications. We enrolled 11 patients who underwent trabeculectomy and could be followed for ≥3 years. We used the value of inclination of the mean deviation (MD) slope (dB/year) as the speed of progression of visual field defects as an index of surgical efficacy. We compared the MD slope before and after trabeculectomy. Results: The mean preoperative IOP was 11.1±1.4 mmHg and the mean postoperative IOP was 6.5±2.5, 8.6±2.8 and 8.8±2.1 mmHg at 1, 2, and 3 years respectively. The inclination value of MD slope significantly improved from -1.19±0.35 to -0.13±0.37 dB/year (p