A retrospective study of ten-year outcomes of glaucoma drainage device surgery in African patients.

Background: Trabeculectomy, a commonly performed glaucoma filtration surgery, is often necessary to lower intraocular pressure and maintain visual function. However, individuals of African descent have been shown to experience higher rates of trabeculectomy failure. This poses a persistent challenge for Ophthalmologists in the region, especially when managing unsuccessful surgeries and complex forms of secondary glaucoma. In such difficult-to-treat cases, where standard surgical methods have failed or are anticipated to fail, glaucoma drainage devices are frequently utilized. This review aims to assess the efficacy and safety of Glaucoma drainage device (GDD) surgery in African eyes with glaucoma Materials and methods: A retrospective review of clinical records of 283 African patients that had Glaucoma drainage device implantation surgery done from November 2014 to November2024 with at least 1 month follow up at Eye foundation Hospital Group. The data was retrieved from Electronic medical records (Indigo) and patients’ charts. The demographics, preoperative IOP (the highest IOP recorded before surgery and postoperative intraocular pressures at day 1, 1month to 120months, the number of glaucoma medications used preop and postop at the last clinic follow up visit, the preop visual acuity (snellen chart and converted to logMar) and at last clinic visit, IOP related surgeries, lasers done before and after GDD surgery and post-op complications were retrieved. All data were cross checked for accuracy, entered in proforma and were analyzed using commercially available statistical data management software-Epi-info version 3.5.1, 7.2.5. Continuous variables were illustrated in the form of mean ±SD and categorical variables were shown in the form of frequency and percent. Complete success is defined as intraocular pressure reduction of 20% or more in Preop intraocular pressure, Qualified success as intraocular pressure <21mmHg and <18mmHg with or without medication. Primary outcome measures were post op intraocular pressure, cumulative probability failure, visual acuity changes at 1 year, 3, 5, and 7 years. The secondary measures were the postop number of medications and complications. Result: Complete success was achieved in 84.5%, 78.0%, 94.1%, 100% at 1year, 3, 5 and 7years respectively. Qualified success was achieved in 78.6%, 86.0%, 82.4% and 66.7% at 1year, 3, 5, and 7 years respectively with IOP at <21mmHg. At IOP of <18mmHg qualified success was achieved in 72.6%, 82.0%,76.5% and 66.7% at 1 year, 3,5, and 7 years respectively. Complications occurred in 3.2%, which included macula edema, 1.8%, ptosis, exposed Glaucoma drainage device, dislocation of tube and encapsulated bleb, 1.1% each. Hypotony, choroidal effusion and branch retinal vein occlusion occurred in 0.7% of cases. Endophthalmitis occurred in 0.4% of cases. Conclusion: A glaucoma drainage device can safely and effectively manage refractory glaucoma, even over an extended period of time in Africans.