Wong, Natalie Shi Qi

The iStent series constitutes a range of trabecular bypass minimally invasive glaucoma surgery (MIGS) devices, which offers intraocular pressure (IOP) reduction with favourable safety profiles, in patients with open-angle glaucoma (OAG). Having undergone significant evolution since its initial US FDA-approval in 2012, successive generations address previous limitations, while enhancing IOP-lowering efficacy through device and delivery system design iterations. Longer-term and real-world iStent data demonstrate the durability of IOP- and medication-lowering outcomes with minimal complications, while preliminary studies across a wider spectrum of glaucoma subtypes and severities provide limited evidence of successful outcomes beyond mild-to-moderate OAG, both with and without concomitant cataract surgery. Aqueous humour outflow assessment and novel intra-operative techniques may further facilitate more accurate and effective iStent positioning. Despite typically higher upfront costs, results from both cost-effectiveness and patient-reported outcome studies are encouraging. Combination MIGS with the iStent, leveraging on the multiple mechanisms of actions of various procedures, may provide greater IOP-lowering efficacy without compromising safety. With expanding clinical data and progressive enhancements, iStent technology is likely to remain a key component of the evolving MIGS landscape.

A systematic review was conducted of studies published up to 30 August 2024. Studies comparing conventional visual field (VF) indices, ability to detect central visual field defects (CVFDs), structure–function (S-F) concordance, and test characteristics across the HVF 24-2C SITA-Faster, 24-2 SITA-Standard/Faster, and 10-2 SITA-Standard/Fast tests were included. Eight studies with 1239 subjects (49.1% male; mean age, 54.8–66.9 years) were analyzed. The 24-2C produced similar global VF indices compared to the 10-2 and 24-2 (Standard/Faster) (ICC = 0.95 and 0.80, p < 0.001), detected more VF defects and CVFD clusters, and demonstrated greater S-F concordance than the 24-2 (Standard/Faster). Although the 10-2 (Standard/Fast) detected significantly more CVFDs and had a greater S-F concordance, the agreement between the 24-2C and 10-2 grids was substantial (ĸ = 0.488 to 0.708). The 24-2C was also faster compared to the 24-2 Standard and 10-2 (Standard/Fast), with comparable false positives, higher false negatives, and fewer fixation losses than the 24-2 Standard. In conclusion, the HVF 24-2C is quicker and identifies more CVFDs than the 24-2 grid, demonstrates high agreement with the 10-2 grid, and aids in CVFD screening.