Short-term changes in Bruch's membrane opening-based morphometrics during the first week after trabeculectomy

Purpose To evaluate the dynamics of Brach's membrane opening-based morphometrics of the optic nerve head (ONH) using spectral-domain optical coherence tomography (SD-OCT) during the first week after glaucoma surgery by trabeculectomy with mitomycin C. Methods Prospective, longitudinal analysis of 25 eyes of 25 patients treated by trabeculectomy. Twenty-four eyes had evaluable postoperative SD-OCT examinations. Bruch's membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness were analyzed at baseline before surgery, 1 day, 2 to 3 days, and 1 week after surgery. Changes compared to baseline were correlated to intraocular pressure (TOP). Results One day after surgery, the mean BMO-MRW changed by+ 26.17 mu m, p= 0.001 (mean IOP reduction by 17.01 mmHg) This increase persisted on day 2-3 with a mean increase of BMO-MRW of+25.33 mu m, p =0.001 (mean IOP reduction by 20 46 mmHg) and by week 1 with a mean BMO-MRW increase of+ 33.17 mu m, p < 0.001 (mean IOP reduction by 22.55 mmHg) The increase in BMO-MRW correlated significantly with the reduction of TOP on day 1 (Spearman's rho rho= 0.656, p= 0.003) and d2-3 (Spearman's rho rho= 0.479, p= 0.038). There was no statistically significant correlation found between the IOP and the increase in BMO-MRW in week 1. RNFL thickness showed no significant changes at day 1 as well as days 2-3 (p >= 0.078, respectively). It showed a small but significant increase in week 1 by 3.94 mu m, p = 0.015. Conclusions Structural reversal of disc cupping in BMO-MRW occurs as early as 1 day after trabeculectomy and correlates to the extent of the IOP reduction. During the whole first week after surgery, a strong increase in BMO-MRW can be noted. The changes in BMO-based parameters need to be considered when evaluating patients' longitudinal follow-up.