Abstract
BACKGROUND: The Kahook Dual Blade (KDB) is a minimally invasive glaucoma surgery (MIGS) device designed to excise a strip of trabecular meshwork, enhancing aqueous outflow via Schlemm's canal. While its efficacy is well-documented, there is limited evidence comparing outcomes between anatomical quadrants treated. OBJECTIVES: To compare intraocular pressure (IOP) reduction, medication burden, visual acuity improvement, and complication rates between nasal and inferior quadrant sectoral excisional goniotomy with KDB combined with cataract surgery. DESIGN: Retrospective cohort study. METHODS: Medical records of patients with primary open-angle glaucoma who underwent combined phacoemulsification and KDB goniotomy between January 2020 and June 2025 at a single tertiary academic center were reviewed. Patients were grouped by treatment location (nasal vs inferior). Primary outcomes were IOP and the number of glaucoma medications; secondary outcomes included best-corrected visual acuity (BCVA) and adverse events. Multivariate linear regression was used to adjust for baseline differences between groups. RESULTS: Sixty-four eyes (nasal: 50; inferior: 14) met the inclusion criteria. Baseline IOP and BCVA were similar between groups, though the inferior group had fewer medications (1.93 vs 2.68; p = 0.045) and milder visual field loss (MD -8.39 vs -15.18; p = 0.04). Mean treatment extent was approximately 90° in both groups. Both groups achieved significant IOP reduction at all follow-up points, with no long-term differences. At postoperative week 1, the inferior group had higher IOP (18.50 vs 13.99 mmHg; p = 0.0433), potentially due to gravity-dependent hyphema. Medication burden decreased in both groups, with a non-significant trend toward fewer drops in the inferior group. BCVA improved similarly, and complication rates were low and comparable, with no serious adverse events. CONCLUSION: Nasal and inferior quadrant KDB goniotomy combined with cataract surgery yields comparable long-term outcomes in IOP, medication burden, visual acuity, and safety. Quadrant selection may be guided by intraoperative visualization and patient-specific anatomy without compromising efficacy.