The Efficacy and Safety of Reducing Intraocular Pressure to Single-digit Levels in Normal-Tension Glaucoma: A Systematic Review

Abstract

Purpose: This systematic review aims to evaluate the efficacy and safety of lowering intraocular pressure (IOP) to single-digit levels in patients with progressive normal-tension glaucoma (NTG). Material and Methods: A literature search was conducted in PubMed, Scopus, and Web of Science. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist. We selected studies involving NTG patients who underwent interventions to further reduce IOP to single-digit levels and that reported data on the efficacy of these interventions. Study outcomes include visual field (VF) progression rates, assessed through the VF mean deviation (MD) slope and changes in IOP and IOP-lowering medication use. Results: Nine observational studies, including 270 eyes, were analyzed. Trabeculectomy was performed across all studies. One study compared trabeculectomy with prostaglandin analogs. On average, IOP decreased from 14.77 ± 0.95mmHg preoperatively to 9.82 ± 1.55mmHg postoperatively, reflecting a mean reduction of 33,65 ± 10.37%. This reduction slowed glaucoma progression, as indicated by an improvement in the mean VF MD slope from -0.91 ± 0.27dB/year preoperatively to -0.25 ± 0.16dB/year postoperatively. Single-digit IOP levels were shown to be both achievable and sustainable. The most common postoperative complications included hypotony-related complications and hyphema. Conclusions: Achieving single-digit IOP levels is associated with a reduction in visual field progression. However, the balance between efficacy and safety must be considered, since aggressive IOP reduction is also associated with a higher risk of hypotony-related complications.