Dynamics of structural reversal in Bruch's membrane opening-based morphometrics after glaucoma drainage device surgery.

Purpose: Structural reversal of disc cupping is a known phenomenon after trabeculectomy. The aim of this retrospective, longitudinal, cross-sectional analysis was to evaluate the postoperative dynamics of Bruch's membrane opening-based morphometrics of the optic nerve head following glaucoma drainage device surgery.

Methods: Forty-three eyes, treated by glaucoma drainage device surgery, were included in the study. Individual changes in the spectral domain optic coherence tomography (SD-OCT) parameters Bruch's membrane opening minimum rim width (BMO-MRW), Bruch's membrane opening minimum rim area (BMO-MRA) and peripapillary retinal nerve fiber layer (RNFL) thickness as well as mean defect in 30-2 perimetry were analyzed. Changes were correlated to postoperative intraocular pressure levels over time. Available follow-up visits were aggregated and grouped into a short-term follow-up (20 to 180 days after surgery), a midterm follow-up (181 to 360 days after surgery) and a long-term follow-up (more than 360 days after surgery).

Results: In short-term follow-up, BMO-MRW and BMO-MRA increased significantly (p <= 0.034). This increase correlated negatively with the intraocular pressure at the time of the follow-up (Pearson's rho = - 0.49; p = 0.039). From 6 months after surgery on, there was no statistically significant change in BMO-MRW and BMO-MRA (p >= 0.207). RNFL thickness and mean defect of 30-2 perimetry showed no significant changes after GDD implantation (p >= 0.189).

Conclusions: Lowering of intraocular pressure by glaucoma drainage device surgery leads to an increase of Bruch's membrane opening based parameters in the first 6 months after surgery. These changes have to be taken into account when evaluating patients' longitudinal follow-up after glaucoma drainage device implantation.