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

To determine the change in global and regional Humphrey visual fields (VF) after glaucoma drainage device (GDD) implantation over a 3-year follow-up period.

Retrospective interventional case series.

Patients undergoing GDD placement from between 2010 and 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), CIGTS (Collaborative Initial Glaucoma Treatment Study) score of 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.

A total of 106 eyes from 95 patients were included. Mean IOP ± SD was reduced from 23.1 ± 8.5 mm Hg to 12.7 ± 3.1 mm Hg at 3-year follow-up (P < .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 = .01). No regional metrics showed worsening at follow-up examinations. Defects in the superior hemifield were more common than in the inferior hemifield at baseline and follow-up examinations for all regional metrics. Pre-operative number of glaucoma medications was associated with worsening on CIGTS_TDP.

Overall, GDD surgery is effective at stabilizing VF function over 3 years of follow-up. The superior hemifield is affected more than other regions. The number of pre-operative glaucoma medications is associated with mild VF progression, measured by CIGTS_TDP.