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

Hiroshi Katayama, Naoki Tojo, Naoki Toyoda, Atsushi Hayashi Department of Ophthalmology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, JapanCorrespondence: Atsushi Hayashi, Department of Ophthalmology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan, Tel +81-76-434-7363, Fax +81-76-434-5037, Email [email protected]: 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< 0.001). Trabeculectomy significantly decreased IOP and slowed the progression of visual field defects.Conclusion: The results suggest that trabeculectomy might be effective even in patients with very low preoperative IOP.Keywords: trabeculectomy, glaucoma, low IOP, NTG, MD slope