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Comparison of Surgical Outcomes Between Microhook Ab Interno Trabeculotomy and Goniotomy with the Kahook Dual Blade in Combination with Phacoemulsification: A Retrospective, Comparative Case Series



To study surgical outcomes of patients with a minimum of 6 months of follow-up after undergoing combined phacoemulsification with either microhook ab interno trabeculotomy (μLOT-Phaco) or goniotomy using the Kahook Dual Blade (KDB-Phaco).


This retrospective comparative case series examined 22 μLOT-Phaco eyes and 81 KDB-Phaco eyes that underwent surgery between December 2016 and October 2018. Data collected from medical records included pre- and postoperative intraocular pressure (IOP), number of IOP-lowering medications and complication occurrence. Potential risk factors for failure were determined by Cox proportional hazards regression analysis. Surgical failure was defined as an IOP of > 20 mmHg, < 20% reduction in preoperative IOP or additional glaucoma surgery. Kaplan-Meier survival analysis was used to assess success rates. Score matching used a genetic algorithm consisting of type of glaucoma.


Of 81 KDB-Phaco eyes, 22 eyes were matched to 22 μLOT-Phaco eyes. Mean IOP in the μLOT-Phaco group decreased from 24.7 ± 6.4 mmHg at baseline to 14.4 ± 3.0 mmHg (P < 0.01) and 13.0 ± 2.5 mmHg (P < 0.01) at 6 and 12 months, respectively. Mean IOP in the KDB-Phaco group decreased from 23.2 ± 5.4 mmHg to 15.8 ± 3.3 mmHg (P < 0.001) and 16.7 ± 2.1 mmHg (P < 0.001), respectively. Mean number of preoperative IOP-lowering medications in the μLOT-Phaco group at baseline was 3.7 ± 1.0, which decreased to 1.4 ± 1.5 (P < 0.01) at 12 months, while in the KDB-Phaco group it decreased from a baseline value of 3.3 ± 1.2 to 1.1 ± 1.4 (P < 0.01). Probability of qualified success at 12 months in the μLOT-Phaco and KDB-Phaco groups was 71.8% and 62.2%, respectively (P = 0.75). Similar postoperative complications were found between the groups.


Use of μLOT-Phaco and KDB-Phaco resulted in comparable IOPs and reductions in the number of medications.

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  1. 1.

    Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006;90:262–7.

    CAS  Article  Google Scholar 

  2. 2.

    Jhonson M. What controls aqueous humor outflow resistance? Exp Eye Res. 2006;82:545–57.

    Article  Google Scholar 

  3. 3.

    Minckler DS, Baerveldt G, Alfaro MR, Francis BA. Clinical results with the Trabecutome for treatment of open-angle glaucoma. Ophthalmology. 2005;112:962–7.

    Article  Google Scholar 

  4. 4.

    Seibold LK, Soohoo JR, Ammar DA, Kahook MY. Preclinical investigation of ab interno trabeculectomy using a novel dual-blade device. Am J Ophthalmol. 2013;155:524–9.

    Article  Google Scholar 

  5. 5.

    Sato T, Kawaj T, Hirata A, Mizoguchi T. 360-degree suture trabeculotomy ab interno to treat open-angle glaucoma: 2-year outcomes. Clin Ophthalmol. 2018;12:915–23.

    CAS  Article  Google Scholar 

  6. 6.

    Tanito M, Sano I, Ikeda Y, Fujihara E. Shore-term results of microhook ab interno trabeculotomy, a novel minimally invasive glaucoma surgery in Japanese eyes: initial case series. Acta Ophthalmol. 2017;95:e354–60.

    Article  Google Scholar 

  7. 7.

    Le C, Kazaryan S, Hubbell M, Zurakowski D, Ayyala RS. Surgical Outcomes of phacoemulsification followed by iStent implantation versus goniotomy with the Kahook Dual Blade in patients with mild primary open-angle glaucoma with a minimum of 12-month follow-up. J Glaucoma. 2019;28:411–4.

    Article  Google Scholar 

  8. 8.

    ElMallah MK, Seibold LK, Kahook MY, KDB Goniotomy Study Group, et al. 12-month retrospective comparison of Kahook Dual Blade excisional goniotomy with istent trabecular bypass device implantation in glaucomatous eyes at the time of cataract surgery. Adv Ther. 2019;36:2515–27.

    Article  Google Scholar 

  9. 9.

    Dorairaj SK, Kahook MY, Williamson BK, et al. A multicenter retrospective comparison of goniotomy versus trabecular bypass device implantation in glaucoma patients undergoing cataract extraction. Clin Ophthalmol. 2018;12:791–7.

    Article  Google Scholar 

  10. 10.

    Omoto T, Fujishiro T, Asano-Shimizu K, et al. Comparison of the short-term effectiveness and safety profile of ab interno combined trabeculotomy using 2 types of trabecular hooks. Jpn J Ophthalmol. 2020;64:407–13.

    Article  Google Scholar 

  11. 11.

    Tanito M, Ikeda Y, Fujihara E. Effectiveness and safety of combined cataract surgery and microhook ab interno trabeculotomy in Japanese eyes with glaucoma: report of an initial case series. Jpn J Ophthalmol. 2017;61:457–64.

    Article  Google Scholar 

  12. 12.

    Greenwood MD, Seibold LK, Padcliffe NM, et al. Goniotomy with a single-use dualblade: short-term results. J Cataract Refract Surg. 2017;43:1197–201.

    Article  Google Scholar 

  13. 13.

    Dorairaj SK, Seibold LK, Radcliffe NM, et al. 12-month outcomes of goniotomy performed using the Kahook Dual Blade combined with cataract surgery in eyes with medically treated glaucoma. Adv Ther. 2018;35:1460–9.

    Article  Google Scholar 

  14. 14.

    Malvankar-Mehta MS, Iordanous Y, Chen YN, et al. iStent with phacoemulsification versus phacoemulsification alone for patients with glaucoma and cataract: a meta-analysis. PLoS One. 2015;10:e0131770.

    Article  Google Scholar 

  15. 15.

    Shokoohi-Rad S, Karimi F, Zarei-Ghanavati S, Tireh H. Phacoemulsification, visco-goniosynechialysis, and goniotomy in patients with primary angle-closure glaucoma: a comparative study. Eur J Ophthalmol. 2019;1120672119879331.

  16. 16.

    Moghimi S, Latifi G, ZandVakil N, et al. Phacoemulsification versus combined phacoemulsification and viscogonioplasty in primary angle-closure glaucoma: a randomized clinical trial. J Glaucoma. 2015;24:575–82.

    Article  Google Scholar 

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We thank the participants of the study.


This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (20K09827). The Rapid Service Fees were funded by the authors.


All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship for this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval to the version to be published.

Authorship Contributions

Technical assistance for this manuscript was provided by Drs. Yuki Yuasa, Hideaki Okumichi and Yoshiaki Kiuchi. Data collection was provided by Drs. Ryota Aoki, Hiromitsu Onoe and Erina Goda. Analysis and writing of this manuscript were provided by Dr. Ryota Aoki. Editing assistance for this manuscript was provided by Dr. Kazuyuki Hirooka.


Ryota Aoki, Kazuyuki Hirooka, Erina Goda, Yuki Yuasa, Hideaki Okumichi, Hiromitsu Onoe and Yoshiaki Kiuchi declare that they have no conflict of interest and nothing to disclosure.

Compliance with Ethics Guidelines

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (Institutional Review Board of the Hiroshima University: E-1363, Kagawa University Faculty of Medicine: 26-110) and with the Helsinki Declaration of 1964, as revised in 2013. All subjects provided written informed consent in addition to the standard consent for surgery prior to their enrollment and participation in the research study.

Data Availability

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

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Corresponding author

Correspondence to Kazuyuki Hirooka.

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Aoki, R., Hirooka, K., Goda, E. et al. Comparison of Surgical Outcomes Between Microhook Ab Interno Trabeculotomy and Goniotomy with the Kahook Dual Blade in Combination with Phacoemulsification: A Retrospective, Comparative Case Series. Adv Ther 38, 329–336 (2021).

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  • Intraocular pressure
  • Kahook dual blade
  • Microhook
  • Ophthalmology