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Ab interno canaloplasty versus gonioscopy-assisted transluminal trabeculotomy in open-angle glaucoma: a randomised controlled trial
  1. Peng Yin1,
  2. Jiaying Li1,
  3. Yan Shi1,
  4. Kai Cao1,
  5. Ying Han2,
  6. Huaizhou Wang1,
  7. Hanruo Liu1,
  8. Chen Xin1,
  9. Yiwei Wang1,
  10. Julius Oatts2,
  11. Jin Wang1,
  12. Qing Sang1,
  13. Zhen Cheng3,
  14. Ningli Wang1
  1. 1 Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
  2. 2 Ophthalmology, University of California San Francisco, San Francisco, California, USA
  3. 3 Capital Medical University, Beijing, China
  1. Correspondence to Professor Ningli Wang, Beijing Tongren Hospital Department of Ophthalmology, Beijing, China; wningli{at}


Objective To compare the efficacy and safety of ab interno canaloplasty (ABiC) with gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with open-angle glaucoma (OAG).

Method This randomised clinical trial recruited eyes with OAG and no previous incisional ocular surgery, among which 38 were randomised to ABiC and 39 to GATT. Follow-ups were performed at 1, 3, 6 and 12 months postoperatively. The primary outcome measures were intraocular pressure (IOP) and use of glaucoma medication at 12 months postoperatively. The secondary outcome measure was complete surgical success (not requiring glaucoma surgery, IOP ≤21 mm Hg and non-use of glaucoma medications).

Results Both groups had similar demographic and ocular characteristics. A total of 71 of the 77 subjects (92.2%) completed 12-month follow-up. At 12 months, mean IOP was 19.0±5.2 mm Hg in the ABiC group and 16.0±3.1 mm Hg in the GATT group (p=0.003). Overall, 57.2% of ABiC patients and 77.8% of GATT patients were medication free (p=0.06). The number of glaucoma medications was 0.9±1.3 in the ABiC group and 0.6±1.2 in the GATT group (p=0.27). The 12-month cumulative rate of complete surgical success was 56% in the ABiC group and 75% in the GATT group (p=0.09). Three eyes in the ABiC group and one eye in the GATT group required additional glaucoma surgery. Hyphema (87% vs 47%) and supraciliary effusion (92% vs 71%) were noted more often in the GATT group than in the ABiC group.

Conclusions The preliminary result showed that GATT had an advantage over ABiC in IOP reduction for OAG patients, accompanied by favourable safety at 12-month postoperatively.

Trial registration number ChiCTR1800016933.

  • Glaucoma
  • Treatment Surgery

Data availability statement

Data are available upon reasonable request. Please contact for dataset.

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Data availability statement

Data are available upon reasonable request. Please contact for dataset.

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  • PY and JL are joint first authors.

  • Contributors Research design: PY, YS, KC, HW, CX, YW and NW. Data acquisition and/or research execution: PY, JL, KC, HW, JW, QS and NW. Data analysis and/or interpretation: PY, JL, KC, YH, ZC and NW. Manuscript preparation: PY, JL, YS, YH, HL, JO and NW. Guarantor: NW.

  • Funding This study was supported by the National Natural Science Foundation of China, Grant 2017CB822201 from Ministry of Science & Technology of the People’s Republic of China.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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