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Surgical outcomes of excisional goniotomy using the kahook dual blade in severe and refractory glaucoma: 12-month results



To describe the efficacy and safety of goniotomy with trabecular meshwork excision using the Kahook Dual Blade (KDB, New World Medical Inc., Rancho Cucamonga, CA) in patients with severe or refractory glaucoma.


This retrospective multicentre case series reports on 40 eyes with severe or refractory open-angle glaucoma that underwent standalone or combined KDB goniotomy and were followed for 12 months post-operatively in the United-States, Mexico and Switzerland. Surgical success was defined as an intraocular pressure (IOP) reduction ≥20% from baseline at 12 months, with fewer medications than preoperatively. Mean IOP and antiglaucoma medication reduction, probabilities of achieving an IOP ≤16 or 18 mmHg, and adverse events were also analysed.


Mean IOP decreased from 18.1 ± 5.0 mmHg at baseline to 14.8 ± 3.7 mmHg at 12 months (18.2% reduction, P < 0.001). Concomitantly, the mean number of glaucoma medications decreased from 2.5 ± 1.4 to 1.7 ± 1.2 (32% reduction, P = 0.002). The proportion of eyes achieving an IOP reduction of more than 20% from baseline was 37.5% (n = 15) at 12 months. At 12 months, 67.5% and 82.5% achieved a medicated IOP ≤ 16 and ≤18 mmHg, respectively. No severe complications were reported.


Excisional goniotomy with KDB achieves a statistically significant IOP and antiglaucoma medication reduction in severe or refractory glaucoma over a period of 12 months. While its efficacy decreases with time, its favourable safety profile makes it a potentially useful primary or adjunctive procedure in high-risk eyes.

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Fig. 1: Mean intraocular pressure.
Fig. 2: Number of antiglaucoma medications.
Fig. 3: Cumulative probability of success rate.

Data availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.


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Supported in part by the Swiss Glaucoma Research Foundation, Lausanne, Switzerland.

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Authors and Affiliations



All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by, Kaweh Mansouri, Kevin Gillmann and Giorgio Enrico Bravetti. The first draft of the manuscript was written by Giorgio Enrico Bravetti. Kaweh Mansouri and Kevin Gillmann commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Giorgio Enrico Bravetti.

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Competing interests

JPB: Alcon, Allergan, Bausch and Lomb, CorneaGen, Dakota Lions Eye Bank, Equinox, Expert Opinion, Glaucos, Gore, Imprimis/Harrow Health, JNJ, Kala, Kedalion, MELT Pharmaceuticals, MicroOptix, New World Medical, Ocular Surgical Data, Ocular Theraputix, Omega Ophthalmic, Orasis, Oyster Point, RxSight, Surface Inc., Tarsus, Tear Clear, Vittamed, Vance Thompson Vision, Verana Health (Digisight), Visionary Ventures, Zeiss. Lazcano-Gomez GSL-G: New World Medical. BKW: New World Medical. SKD: New World Medical, Iridex. LS: New World Medical. AAA: New World Medical, Aerie Pharmaceuticals, Bausch and Lomb. AM: Allergan, Bausch and Lomb, Iridex, New World Medical. KM: Santen, Sensimed, Topcon, Alcon, Allergan, Optovue, ImplantData. Others: no financial disclosures.

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Bravetti, G.E., Gillmann, K., Salinas, L. et al. Surgical outcomes of excisional goniotomy using the kahook dual blade in severe and refractory glaucoma: 12-month results. Eye (2022).

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