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Hypotony Failure Criteria in Glaucoma Surgical Studies and Their Influence on Surgery Success

Rabiolo, A., Triolo, G., Khaliliyeh, D. , Jin, S. W., Morales, E., Ghirardi, A., Anand, N., Montesano, G. ORCID: 0000-0002-9148-2804, Virgili, G., Caprioli, J. & De Cillà, S. (2024). Hypotony Failure Criteria in Glaucoma Surgical Studies and Their Influence on Surgery Success. Paper presented at the Association for Research in Vision and Ophthalmology Annual Meeting, 23-27 Apr 2023, New Orleans, United States. doi: 10.1016/j.ophtha.2024.01.008


Review hypotony failure criteria used in glaucoma surgical outcome studies and evaluate their impact on success rates.

Systematic literature review and application of hypotony failure criteria to 2 retrospective cohorts.

A total of 934 eyes and 1765 eyes undergoing trabeculectomy and deep sclerectomy (DS) with a median follow-up of 41.4 and 45.4 months, respectively.

Literature-based hypotony failure criteria were applied to patient cohorts. Intraocular pressure (IOP)-related success was defined as follows: (A) IOP ≤ 21 mmHg with ≥ 20% IOP reduction; (B) IOP ≤ 18 mmHg with ≥ 20% reduction; (C) IOP ≤ 15 mmHg with ≥ 25% reduction; and (D) IOP ≤ 12 mmHg with ≥ 30% reduction. Failure was defined as IOP exceeding these criteria in 2 consecutive visits > 3 months after surgery, loss of light perception, additional IOP-lowering surgery, or hypotony. Cox regression estimated failure risk for different hypotony criteria, using no hypotony as a reference. Analyses were conducted for each criterion and hypotony type (i.e., numerical [IOP threshold], clinical [clinical manifestations], and mixed [combination of numerical or clinical criteria]).

Main Outcome Measures
Hazard ratio (HR) for failure risk.

Of 2503 studies found, 278 were eligible, with 99 studies (35.6%) lacking hypotony failure criteria. Numerical hypotony was predominant (157 studies [56.5%]). Few studies used clinical hypotony (3 isolated [1.1%]; 19 combined with low IOP [6.8%]). Forty-nine different criteria were found, with IOP < 6 mmHg, IOP < 6 mmHg on ≥ 2 consecutive visits after 3 months, and IOP < 5 mmHg being the most common (41 [14.7%], 38 [13.7%], and 13 [4.7%] studies, respectively). In both cohorts, numerical hypotony posed the highest risk of failure (HR, 1.51–1.21 for criteria A to D; P < 0.001), followed by mixed hypotony (HR, 1.41–1.20 for criteria A to D; P < 0.001), and clinical hypotony (HR, 1.12–1.04; P < 0.001). Failure risk varied greatly with various hypotony definitions, with the HR ranging from 1.02 to 10.79 for trabeculectomy and 1.00 to 8.36 for DS.

Hypotony failure criteria are highly heterogenous in the glaucoma literature, with few studies focusing on clinical manifestations. Numerical hypotony yields higher failure rates than clinical hypotony and can underestimate glaucoma surgery success rates. Standardizing failure criteria with an emphasis on clinically relevant hypotony manifestations is needed.

Publication Type: Conference or Workshop Item (Paper)
Additional Information: © 2024. This manuscript version is made available under the CC-BY-NC-ND 4.0 license
Publisher Keywords: Glaucoma surgery, Nonpenetrating glaucoma surgery, Randomized controlled study, Retrospective study, Trabeculectomy, 1103 Clinical Sciences, 1113 Opthalmology and Optometry, 1117 Public Health and Health Services, Ophthalmology & Optometry, 3212 Ophthalmology and optometry
Subjects: R Medicine > RD Surgery
R Medicine > RE Ophthalmology
Departments: School of Health & Psychological Sciences
School of Health & Psychological Sciences > Optometry & Visual Sciences
SWORD Depositor:
[thumbnail of OPHTHA-D-23-01936_R3.pdf] Text - Accepted Version
This document is not freely accessible until 8 January 2025 due to copyright restrictions.
Available under License Creative Commons Attribution Non-commercial No Derivatives.

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