Outcomes of Ab-Interno Canaloplasty and Gonioscopy-Assisted Transluminal Trabeculotomy in Eyes with Sustained Intraocular Pressure Elevation Following Intravitreal Injections

Purpose: To evaluate the long-term efficacy and safety of combined ab-interno canaloplasty (ABiC) and gonioscopy-assisted transluminal trabeculotomy (GATT) with the iTrack microcatheter in patients with sustained intraocular pressure (IOP) elevation following intravitreal anti-VEGF or steroid injections. Patients and Methods: This was a retrospective, single-center study of patients who underwent ABiC and GATT with the iTrack microcatheter between 2017 and 2021 for secondary open-angle glaucoma or ocular hypertension following intravitreal injections. Eligible eyes had a preoperative IOP of ≥ 18 mmHg while on maximal tolerated medical therapy. Primary outcomes included IOP and glaucoma medication burden. Surgical success was defined using American Academy of Ophthalmology (AAO) criteria. Subgroup analyses were conducted by etiology (anti-VEGF vs steroid-induced). Kaplan-Meier analysis estimated cumulative success rates. Results: Thirty-four eyes from 30 patients were included, with a mean last follow-up of 15.3± 9.8 months. Mean IOP was reduced by 46%, from 28.1± 6.0 mmHg at baseline to 14.3± 5.6 mmHg (p< 0.001) at the last follow-up, while the number of medications decreased from 2.79± 0.9 to 1.76± 1.5 (p=0.001). Surgical success was achieved in 71% of eyes. Medication-free status was reached in 29% of eyes, compared with none at baseline, and 26% achieved IOP ≤ 15 mmHg without medications. Additional glaucoma procedures were needed in 11.8% of eyes. Combined ABiC and GATT remained effective in eyes receiving post-procedure intravitreal reinjections or prolonged topical steroid use. Kaplan-Meier analysis showed a survival probability above 70% at 25 months. Conclusion: Combined ab-interno canaloplasty and GATT using the iTrack microcatheter is a safe surgical option for selected eyes with sustained IOP elevation following intravitreal injections. The procedure achieved meaningful reductions in IOP and medication use, including in eyes requiring continued intravitreal therapy, supporting a primary surgical effect. Careful patient selection and long-term follow-up remain essential, as a subset of eyes may require additional intervention. Plain Language Summary: Some people who receive eye injections for conditions like macular degeneration or diabetic eye disease may develop higher eye pressure over time. This can lead to glaucoma, a condition that damages the optic nerve and can cause vision loss. Medicines to lower pressure do not always work well enough, and traditional glaucoma surgery can carry risks. We wanted to find out if ab-interno canaloplasty and gonioscopy-assisted transluminal trabeculotomy, combined together, could safely lower eye pressure in these patients. Both surgeries use a fine surgical thread, called a microcatheter, to open the natural drainage system of the eye and improve fluid outflow. We looked back at the medical records of 30 people (34 eyes) who had these combined procedures after developing high eye pressure following repeated injections or steroid treatment. At the latest follow-up visit, eye pressure had dropped by almost half and most people were able to reduce the number of daily eye drops they needed. About three out of four eyes met the standard definition of surgical success, and one in four no longer needed any pressure-lowering medication. Only a small number of patients required another glaucoma operation. Our results suggest that these combined procedures can be an effective and safer option to control high eye pressure after eye injections. This may help reduce the need for more invasive surgery. Long-term follow-up remains important, as some people may still require additional treatment later on. Keywords: microcatheter-assisted glaucoma surgery, secondary open-angle glaucoma, steroid-induced ocular hypertension, anti-VEGF therapy, surgical success criteria