Surgical Outcomes of Glaucoma Drainage Device Implantation in Refractory Glaucoma Patients in Thailand

PURPOSE: To study the surgical outcomes of glaucoma drainage device (GDD) implantation in refractory glaucoma patients. PATIENTS AND METHODS: Retrospective chart review of glaucoma patients undergoing GDD implantation, Ahmed glaucoma valve (AGV), Baerveldt glaucoma implants (BGI), and Aurolab aqueous drainage implantation (AADI) from January 2012 to June 2021. Glaucoma patients were classified into two groups: primary glaucoma including: primary open angle glaucoma (POAG), primary angle closure glaucoma (PACG) and juvenile open angle glaucoma (JOAG) and secondary glaucoma including: neovascular glaucoma (NVG), ocular surgery (vitreoretinal surgery, scleral buckling procedure, postoperative extra capsular cataract extraction, scleral fixation intraocular lens, penetrating keratoplasty), intraocular trauma, uveitis glaucoma, lens-induced glaucoma, pseudoexfoliation glaucoma (PXG), iridocorneal endothelial (ICE) syndromes and Axenfeld Rieger Syndrome. Surgical outcomes were studied. RESULTS: Primary glaucoma included 57 eyes from 49 patients. Secondary glaucoma included 87 eyes from 85 patients. The cumulative probability of complete or qualified success of refractory glaucoma patients at five years were 53.4% (95%CI: 38.4%, 66.3%). Higher success rate was discovered in primary glaucoma at 65.8% (95%CI: 38.4%, 83.3%) than 45.2% (95%CI: 26.9%, 61.9%) in secondary glaucoma group significantly with p=0.003. While the results among success rate, adverse events and complications was not different between types of GDD. Predictors for failure were neovascular glaucoma with unadjusted hazard ratio (HR) 3.62 (95%CI: 1.45, 9.04) with p=0.006, and lens-induced glaucoma with adjusted HR 4.19 (95%CI: 1.10, 15.86) with p=0.035 in multivariable analysis. Tube malposition and occlusion were the most frequent adverse events at 11.11%, corneal decompensation at 5.5%, hypotony at 2% in the nonvalved group, and endophthalmitis at 0.69%. CONCLUSION: Surgical success in refractory primary glaucoma was superior to secondary glaucoma with no difference between nonvalved and valved GDD implantation. Lens-induced glaucoma was a strong predictor for failure in GDD implantation.