Comparison of Outcomes of Glaucoma Drainage Implant Surgery With or Without Prior Failed Trabeculectomy.

Abstract

A comparison of 186 glaucoma patients with mixed diagnoses who underwent nonvalved glaucoma drainage device (GDD) implant surgery showed similar long-term intraocular pressure (IOP), medication, and visual acuity (VA) outcomes between those with prior failed trabeculectomy surgery versus those without. The purpose of this study was to evaluate whether prior failed trabeculectomy adversely affects the outcome of glaucoma tube surgery. A total of 186 eyes of 186 patients who underwent a nonvalved GDD implant surgery by a single surgeon between 1996 and 2015 at a University practice were included. Patients were of mixed diagnoses and over 18 years old. Before the GDD surgery, 65 had a previous failed glaucoma filtering surgery and 121 had no prior glaucoma surgery. Demographic information, preoperative and postoperative IOP, medication, VA, and complications were collected from chart review. No significant difference was noted in mean IOP and mean medication use (13.0 and 12.6 mm Hg on 2.0 and 1.7 medication classes at 5 y postoperatively, respectively), mean VA and change in VA from baseline, or numbers of complications (P>0.05), between eyes that had a prior failed filtration surgery and those that had not. Kaplan-Meier plots for failure over 5 years using a lower limit of <5 mm Hg and an upper limit of ≥18, ≥15, or ≥12 mm Hg did not show a significant difference between groups. Subanalyses were performed to examine only primary glaucoma eyes and results were similar. Further group subanalyses comparing those with baseline IOP ≥25 or <25 mm Hg, age 65 and above or below 65 years and those specifically with Baerveldt 350 mm2 implants also did not show significant differences. Prior failed filtration surgery does not appear to affect the outcome of future GDD surgery.