Comparison of Outcomes of Glaucoma Drainage Implant Surgery with or without Prior Failed Trabeculectomy.

PRCIS A comparison of 186 glaucoma patients with mixed diagnoses who underwent non-valved glaucoma drainage implant surgery showed similar long-term IOP, medication, and VA outcomes between those with prior failed trabeculectomy surgery versus those without. PURPOSE To evaluate whether prior failed trabeculectomy adversely affects the outcome of glaucoma tube surgery. PATIENTS AND METHODS 186 eyes of 186 patients who underwent a non-valved glaucoma drainage implant (GDD) 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. Prior to the GDD surgery, 65 had a previous failed glaucoma filtering surgery and 121 had no prior glaucoma surgery. Demographic information, pre-operative and post-operative intraocular pressure (IOP), medication, visual acuity (VA) and complications were collected from chart review. RESULTS No significant difference was noted in mean IOP and mean medication use (13.0 and 12.6▒mmHg on 2.0 and 1.7 medication classes at 5 years post-operatively 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 five years using a lower limit of <5▒mmHg and an upper limit of ≥ 18, ≥15, or ≥12▒mmHg did not show a significant difference between groups. Sub-analyses were performed to examine only primary glaucoma eyes and results were similar. Further group sub-analyses comparing those with baseline IOP ≥ 25 or < 25▒mmHg, age ≥ 65 or <65 years and those specifically with Baerveldt 350▒mm2 implants also did not show significant differences. CONCLUSION Prior failed filtration surgery does not appear to affect outcome of future GDD surgery.