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Assessing risk factors for postoperative hypotony in Ahmed glaucoma valve implantation surgery



To assess the risk factors associated with the development of hypotony after Ahmed glaucoma valve (AGV) implantation.


One hundred and ninety-three eyes of 177 patients with various types of glaucoma that were treated with AGV implantation were retrospectively evaluated. Intraocular pressure lower than 6 mmHg related to the surgery is defined as postoperative hypotony. Patients’ demographic characteristics, type of glaucoma, preoperative and postoperative visual acuity, necessity of antiglaucoma treatments, lens status, previous ocular surgeries, intraocular pressure (IOP) measurements before and after surgeries, the need for additional procedures and postoperative complications were recorded from the patients’ charts.


Hypotony was seen in 68 of 193 eyes (35.2%) postoperatively. In 45 eyes (23.3%), it has occurred in first postoperative day and in 23 eyes (11.9%) after the first day within the first week. There was no difference in intraocular pressures between two groups in the first year follow-up. Pre- and postoperative best-corrected visual acuities, age and gender were not statistically different between hypotony and no hypotony groups (p > 0.05). Also, lens status, history of previous ocular surgery, type of glaucoma and number of preoperative glaucoma medication usage were not found to be different between groups (p > 0.05).


Potential risk factors such as age, sex, lens status, history of previous ocular surgeries, preoperative glaucoma medication usage or glaucoma type are not found to influence upon postoperative hypotony prevalence for AGV surgery. Surgery type and personal ocular factors, which could not be determined beforehand, could be more important than demographic features.

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The manuscript has no associated data in a data repository.


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Authors and Affiliations



All authors contributed to the study conception and design. The study was designed by Ahmet Kaderli and Gülizar Demirok. Data were provided by Ümit Ekşioğlu as the chairmen of the contributing departments. Data collection was performed by Güner Üney, Mehmet Yakın and Berku Günal. The first draft of the manuscript was written by Ahmet Kaderli and Gülizar Demirok, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

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Correspondence to Ahmet Kaderli.

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Author Kaderli declares that he has no conflict of interest. Author Demirok declares that she has no conflict of interest. Author Üney declares that she has no conflict of interest. Author Yakın declares that he has no conflict of interest. Author Günal declares that he has no conflict of interest. Author Ekşioğlu declares that he has no conflict of interest.

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All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

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Retrospective study design.

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For this type of study (retrospective analysis), formal consent is not required.

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Kaderli, A., Demirok, G., Üney, G. et al. Assessing risk factors for postoperative hypotony in Ahmed glaucoma valve implantation surgery. Int Ophthalmol 41, 3381–3386 (2021).

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  • Ahmed glaucoma valve
  • Risk factors
  • Demographic features
  • Shunt surgery
  • Hypotony