Vitreous occlusion of a glaucoma drainage implant (GDI) can lead to failure of the device and severely elevated intraocular pressure. The pathophysiology of tube obstruction is related to central and anterior displacement of vitreous that is drawn into and condenses within the proximal lumen of the tube. This can occur from days to years following GDI surgery. Successful management of vitreous-tube obstruction generally requires manual removal of the condensed vitreous plug with end-grasping forceps. This technique achieves reversal of tube blockage and restoration of GDI function. Amputation of the incarcerated vitreous alone with vitrectomy or neodymium:yttrium-aluminum-garnet vitreolysis does not consistently restore GDI function and risks persistent intraluminal tube obstruction.