Factors Associated with Increased Neuroretinal Rim Thickness Measured Based on Bruch's Membrane Opening-Minimum Rim Width after Trabeculectomy

Purpose: To investigate the factors associated with an increase in the neuroretinal rim (NRR) thickness measured based on Bruch's membrane opening-minimum rim width (BMO-MRW) after trabeculectomy in patients with primary open-angle glaucoma (POAG). Methods: We analyzed the BMO-MRW using spectral-domain optical coherence tomography (SD-OCT) of patients with POAG who underwent a trabeculectomy for uncontrolled intraocular pressure (IOP) despite maximal IOP reduction treatment. The BMO-MRW was measured before and after trabeculectomy in patients with POAG. Demographic and systemic factors, ocular factors, pre- and post-operative IOP, and visual field parameters were collected, together with SD-OCT measurements. A regression analysis was performed to investigate the factors that affected the change in the BMO-MRW after the trabeculectomy. Results: Forty-four eyes of 44 patients were included in the analysis. The IOP significantly decreased from a preoperative 27.0 mmHg to a postoperative 10.5 mmHg. The mean interval between the trabeculectomy and the date of post-operative SD-OCT measurement was 3.3 months. The global and sectoral BMO-MRW significantly increased after trabeculectomy, whereas the peripapillary retinal nerve fiber layer thickness did not show a difference between before and after the trabeculectomy. Younger age and a greater reduction in the IOP after the trabeculectomy were significantly associated with the increase in the BMO-MRW after trabeculectomy. Conclusions: The NRR thickness measured based on the BMO-MRW increased with decreasing IOP after trabeculectomy, and the increase in the BMO-MRW was associated with the young age of the patients and greater reduction in the IOP after trabeculectomy. Biomechanically, these suggest that the NRR comprises cells and substances that sensitively respond to changes in the IOP and age.

Automated summary

The purpose of this study was to investigate factors associated with an increase in neuroretinal rim (NRR) thickness measured based on Bruch's membrane opening-minimum rim width (BMO-MRW) after trabeculectomy in patients with primary open-angle glaucoma. The results showed that NRR thickness measured based on BMO-MRW increased with decreasing intraocular pressure post-trabeculectomy, with younger patients and greater IOP reduction associated with the increase in BMO-MRW. Biomechanically, the NRR seems to comprise cells and substances sensitive to changes in IOP and age.