Ahmed valve implant and its place in the surgical treatment of glaucoma

Abstract

PURPOSE. To determine the indications for Ahmed glaucoma valve implantation by analyzing the duration and regimen of hypotensive therapy, and the configuration of previous interventions.METHODS. Retrospective evaluation of the duration and intensity of therapeutic treatment, and the configuration of laser and surgical procedures in a group of 139 patients (153 interventions) who underwent Ahmed glaucoma valve implantation in 2009–2011, and another group of 270 patients (272 interventions) who were treated in 2019–2010.RESULTS. The average age of candidates for implantation of the Ahmed valve increased from 63 y.o. in 2009–2011 to 70 y.o. in 2019–2020. The treatment preceding Ahmed valve implantation had extended in duration from 8.8±1.4 to 11.2±1.1 years leading to an increase in cumulative preservative toxicity from 9 293.8±968.6 to 10 038.1±888.9 µg. The main classes of intraocular pressure (IOP)-lowering drugs were prostaglandin analogues (75.4% in 2009–2011 and 77.1% in 2019–2020), carbonic anhydrase inhibitors (75.4% and 82.6%), and beta-blockers (57.4% and 61.1% accordingly). Laser trabeculoplasty was performed in only 11.8% and 28.7% of cases, respectively. Hypotensive filtering operations preceded valve implantation in 63.4% (2009–2011) and 80.5% of cases (2019–2020), while in the rest of patients the installation of the Ahmed device was the first surgical procedure. Despite treatment, the rate of glaucoma progression to an advanced stage increased from 62.1% in 2009–2011 to 82.7% in 2019–2020.CONCLUSION. With increase in the duration of conservative management of glaucoma its progression continues, while the increased preservative toxicity reduces the effectiveness of conjunctival surgery. In conclusion, earlier switch to surgical methods of IOP normalization involving the use of the Ahmed valve is advisable not only in secondary, but also in primary open-angle glaucoma treated conser-vatively for a long (over 7–8 years) period.