Evaluation of Long-Term Visual Field Function in Patients Undergoing Glaucoma Drainage Device Implantation.

PURPOSE: To determine the change in global and regional Humphrey visual field (VF) after glaucoma drainage device (GDD) implantation over 3-year follow-up. DESIGN: Retrospective interventional case series METHODS: Patients undergoing GDD placement from 2010-2015 with reliable preoperative and yearly postoperative VF measurements were included. Clinical parameters were compared between preoperative and follow-up visits, including visual acuity, intraocular pressure (IOP), number of glaucoma medications, global VF metrics (mean deviation (MD), pattern standard deviation (PSD), Collaborative Initial Glaucoma Treatment Study (CIGTS) score on total deviation probability (CIGTS_TDP) and pattern deviation probability (CIGTS_PDP)), and regional metrics (regional total deviation (TD), regional pattern deviation (PD), and regional CIGTS_TDP and CIGTS_PDP). Multivariate regression analyses were performed to determine risk factors for VF worsening after GDD surgery. RESULTS: A total of 106 eyes from 95 patients were included. IOP (mean+/-standard deviation) was reduced from 23.1+/-8.5 mmHg to 12.7+/-3.1 mmHg at 3-year follow-up (P<0.001). MD, PSD and global CIGTS_PDP showed no significant changes in follow-up, whereas global CIGTS_TDP showed mild progression from 10.7 to 12.8 at 3-year follow-up (p = 0.01). No regional metrics showed worsening in follow-up. Defects in the superior hemifield was more common than in inferior hemifield at baseline and follow-ups for all regional metrics. Pre-operative number of glaucoma medications was associated with worsening on CIGTS_TDP. CONCLUSION: Overall, GDD surgery is effective at stabilizing VF function over 3-years of follow-up. The superior hemifield is affected more compared to the other regions. The number of pre-operative glaucoma medications is associated with mild VF progression measured by CIGTS_TDP.