Short- to Medium-Term Outcomes of Kahook Dual Blade Excisional Goniotomy with Concomitant Phacoemulsification: a pan-Canadian Study

Authors: Ali Salimi¹, Oscar Kasner¹, Steven Schendel², Marc Mydlarski¹, Dima Kalache¹, Lautaro Vera¹, Rob Pintwala², Paul Harasymowycz³. ¹McGill University, ²University of British Columbia, ³University of Montreal.

Author Disclosures: A. Salimi: None. O. Kasner: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Labtician Ophthalmics. S. Schendel: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Labtician Ophthalmics. M. Mydlarski: None. D. Kalache: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Labtician Ophthalmics. L. Vera: None. R. Pintwala: None. P. Harasymowycz: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Labtician Ophthalmics.


Abstract Body: 

Purpose: The short-term outcomes of ab-interno excisional goniotomy using Kahook Dual Blade (KDB) have been previously investigated. Few studies reported the medium-term outcomes of this minimally invasive glaucoma surgery, among which the functional and structural markers of disease stability were often omitted. The present study assessed the efficacy and safety of KDB goniotomy combined with cataract surgery in eyes with various glaucoma subtypes and severities while also evaluating the functional and structural measures of disease stability using visual field and optical coherence tomography (OCT) of the optic nerve, respectively. 

Study Design: Consecutive case series from multiple surgical sites across Canada. 

Methods: Glaucomatous eyes with cataract that underwent KDB goniotomy with cataract surgery and had a minimum follow-up data of one-year postoperative were included. Efficacy outcomes included surgical success as well as the postoperative change in intraocular pressure (IOP) and glaucoma medication use at the last postoperative follow-up visit. Safety included best-corrected visual acuity (BCVA), cup-to-disc ratio (CDR), visual field mean deviation (VF-MD), retinal nerve fiber layer (RNFL) thickness, and adverse events. 

Results: A total of 106 eyes of 88 patients were included in the study with an average follow-up (FU) duration of 18.0±7.5 months (range [12-47] months). At FU, IOP decreased by 25% from 18.9±5.3 mmHg preoperatively to 14.2±3.4 mmHg (p<0.001), and mean medication use reduced by 17% from 2.3±1.3 medications to 1.9±1.3 (p<0.001). The surgical success rate was 93% as 7 eyes underwent a subsequent glaucoma surgery due to inadequate IOP control or evidence of disease progression. At FU, the postoperative improvement in BCVA was preserved (p<0.001), and CDR, VF-MD, and RNFL thickness remained stable. Favorable safety included no intraoperative complications and few, transient, postoperative adverse events. 

Conclusions: The real-world data from this reasonably-sized multi-center Canadian study supports the high surgical success and efficacy of KDB goniotomy combined with cataract surgery in reducing IOP and glaucoma medication use. Additionally, for the first time, our results demonstrate the short- to medium-term stabilization of disease progression evidenced through the visual field and RNFL thickness measures.

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