Background: The ocular pulse amplitude (OPA) is the difference between the minimum and maximum values of the pulsatile intraocular pressure (IOP) wave contour. The OPA depends on ocular perfusion and IOP, which are both affected by a trabeculectomy (TE). The aim of this study was to investigate how the OPA changes after TE and whether an early change in OPA can be used as a prognostic marker for a successful long-term outcome. Methods: Fourteen consecutive patients (26-84 years old) with medically uncontrolled primary open-angle or pseudoexfoliation glaucoma were included in the study. IOP and OPA were measured with a dynamic contour tonometer before and after TE on days -1, +1, +7, +14, +21, +28, +42, +56, +70, and +84. The OPA of the contralateral eye was used to control for variations in systemic haemodynamics. TE was regarded as successful if a persistent drop in IOP of at least 20% without the use of IOPlowering treatment was achieved. Data were analysed using receiver operating characteristic curves, Kaplan-Meier survival curves and Mann-Whitney two-sample analysis.