Risk factors for postoperative structural reversal of disc cupping in Bruch membrane opening-based morphometry of the optic nerve head for glaucoma

Purpose To identify risk factors for changes in Bruch’s membrane opening-based optical coherence tomography (OCT) parameters after glaucoma surgery and to evaluate duration and dynamics of structural reversal of disc cupping (SRDC) in three different types of glaucoma surgery. Design Retrospective, interventional case series. Methods Evaluation of 151 eyes of 151 patients who received trabeculectomy, ab-interno trabeculotomy or glaucoma drainage device (GDD) surgery. Dynamics of postoperative change in Bruch membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fibre layer thickness in spectral-domain OCT were assessed. Multiple linear regression models identified risk factors for occurrence and magnitude of SRDC. Results Compared with baseline, BMO-MRW increased significantly up to the 9-month follow-up (p=0.048) after surgery. A multiple regression model for all patients showed a high relative reduction in intraocular pressure (IOP) (standard β=−0.272, p<0.001), an early date of follow-up ( stand β=−0.280, p<0.001) and GDD as surgical procedure (standard β=0.169, p=0.027) as significant risk factors for SRDC. Within the first 9 months after intervention, a low postoperative IOP (standard β=−0.469, p < 0.001), a young age (standard β=−0.423, p<0.001) and a short axial length (standard β=−0.235, p = 0.040) had a significant impact on the BMO-MRW increase. Conclusion In this set of patients with glaucoma undergoing different types of IOP-lowering surgery, significant SRDC was seen up to 9 months postoperatively. Risk factors for the extent of SRDC were younger age at surgery, early hypotonia or low postoperative IOP and hyperopia.