This retrospective interventional case series assessed changes to visual fields after implantation of a glaucoma drainage device (Baerveldt, Ahmed or Molteno Devices) between 2010 and 2015. A total of 106 eyes from 96 patients were included in the final analysis and were followed-up for three years. All patients included in the case series had reliable pre- and postoperative visual fields. Mean IOP changed from 23.1 ±8.5mmHG preoperatively to 12.7 ±3.1mmHG at three years postoperatively (p<0.001). Mean deviation, Pattern deviation and Global Initial Collaborative Treatment study pattern deviation probability (CIGTS_PDP) showed no significant changes in follow-up. Global CIGTS Total pattern deviation (CIGTS_TPD) showed mild progression from 10.7 to 12.8 at three-year follow-up. The number of glaucoma medications decreased from 2.7 ±0.8 preoperatively to 1.5 ±1.2 at three years postoperatively. They found that preoperative number of glaucoma medications was associated with worsening on CIGTS_TPD. This research shows that glaucoma drainage device surgery is effective at stabilising visual field loss in glaucoma patients. However, longer-term studies are needed for long-term outcomes.