Surgical Management of Intraocular Pressure With Ab Interno Canaloplasty in Postkeratoplasty Patients: 12-Month Results

Consistency in Standalone Canaloplasty Outcomes Using the iTrack Microcatheter

Purpose

To study the consistency in outcomes of standalone canaloplasty performed via an ab-interno surgical technique in reducing intraocular pressure (IOP) and number of medications in uncontrolled open-angle glaucoma (OAG) eyes over a 12-month period.

Methods

This retrospective multicenter case series included patients who underwent standalone canaloplasty via an ab-interno surgical technique using the iTrack microcatheter (Nova Eye, Inc., Fremont, USA) and had preoperative uncontrolled OAG (IOP≥18mmHg) along with no previous glaucoma surgery. The iTrack microcatheter is used to circumnavigate 360° and viscodilate Schlemm's canal. Consistency of IOP and medications reduction on an eye-by-eye basis were evaluated to understand the outcomes in each single eye.

Results

Sixty-four eyes of 60 patients (age 71.5±13.4 years) were included. Six eyes (9%) that underwent additional glaucoma surgery were considered a failure and were subsequently excluded from analysis. At 12 months, IOP was reduced in 57 of the 58 (89%) remaining eyes; one eye had the same IOP with a reduced number of medications. Of the 57/58 eyes with a reduced IOP: 44 eyes (69%) required fewer medications; 12 eyes (19%) required the same number of medications. Of these 58 eyes, 78% of eyes had a ≥20% reduction in IOP compared to baseline; 69% eyes had a postoperative IOP ≤15 mmHg, and 86% eyes ≤18 mmHg at 12 months. Forty percent of the eyes were medication-free at 12 months compared to none at baseline.

Conclusion

Canaloplasty performed via an ab-interno surgical technique as a standalone procedure consistently reduced IOP and glaucoma medications in almost all eyes.

Incidence and Clinical Characteristics of Postoperative Endophthalmitis After Ab-Interno Canaloplasty

Introduction

Postoperative endophthalmitis (POE) is a rare but devastating complication of ophthalmic surgeries. Microinvasive glaucoma surgery (MIGS) procedures have become increasingly utilized for the surgical reduction of intraocular pressure (IOP). Ab-interno canaloplasty (ABiC) is a popular MIGS procedure, but POE rates and clinical effects following ABiC have not been studied.

Methods

This study conducted a retrospective review of all consecutive cases of either standalone ABiC or combined ABiC with phacoemulsification performed at a tertiary care academic referral center from 2015 to 2021. Exclusion criteria included a history of incisional glaucoma surgery, retinal surgery, or additional concurrent microinvasive glaucoma surgery (MIGS) at the time of ABiC. The rates of POE after ABiC were calculated with 95% confidence intervals (CI) based on the Clopper-Pearson exact method.

Results

Of 3256 cases of ABiC, one case (0.03%, 1/3256, 95% CI: 0.00–0.17%) of post-ABiC endophthalmitis was identified. The rate of POE in standalone ABiC was 0.00% (0/1332 cases, 95% CI: 0.00–0.28%), whereas the rate in combined ABiC with phacoemulsification was 0.05% (1/1924 cases, 95% CI: 0.00–0.29%). Additionally, the rate of POE following stand-alone cataract surgery, 0.10%, 11/11,470 cases, 95% CI: 0.05–0.17%), total cataract surgeries, 0.06% (17/28,013 cases, 95% CI: 0.04–0.10%), total MIGs, excluding ABiC, surgeries, 0.08%, (3/3845 cases, 95% CI: 0.02–0.23%) portray non-inferiority of ABiC in the risk of POE. The case of ABiC-POE presented four days after surgery and required a vitreous tap with intraocular injection of antibiotics and pars plana vitrectomy. No causative organism was identified. A final 1-year follow-up revealed a corrected distance visual acuity of 20/40 and stable glaucoma.

Conclusion

The rate of POE after ABiC (1 per 3256 cases) is statistically non-inferior to the reported incidence of POE after other MIGS and incisional glaucoma surgeries.