Abstract
Purpose :
To systematically review hypotony failure criteria used in the glaucoma surgical studies.
Methods :
We performed a systematic review on MEDLINE searching for glaucoma surgical techniques providing ab externo (e.g., trabeculectomy, glaucoma drainage devices, deep sclerectomy, Preserflo MicroShunt, Express shunt) or ab interno (e.g., Xen Gel) subconjunctival filtration. Patients receiving glaucoma surgeries targeting trabecular meshwork and suprachoroidal space were not included. Both stand-alone and combined surgeries were included. Only studies reporting success rates were included. Only studies published in English and conducted on human subjects were included. We filtered search results for articles published between January 1, 2010, to November 21, 2022, and selected the following article types: clinical study, clinical trial (all types), comparative study, multicenter study, and observational study. Two independent investigators screened titles and abstracts to select studies to include and extracted hypotony definitions (if any) used as surgical failure criteria. Discordance was solved by open adjudication, and in case of disagreement, a third investigator was involved in making a final decision. Study outcomes were specific hypotony definitions, their type (i.e., numerical, clinical, mixed), and their prevalence in the current literature.
Results :
Among the 2,503 studies identified through database search, 278 were eligible (Fig 1). Ninety-nine (35.6%) studies had no hypotony failure criteria; numerical hypotony (IOP below a certain threshold (expressed in mmHg), regardless of hypotony complications) was the most used failure criterion (157 studies [56.5%]). A minority of studies had clinical complications of hypotony among failure criteria, isolated (3 studies [1.1%]) or in combination with a low IOP cutoff (19 studies [6.8%]). Fifty different specific hypotony failure criteria were found (Fig 2), with IOP<6 mmHg, IOP<6 mmHg on ≥2 consecutive visits after 3 months, and IOP<5 mmHg being the most used failure criteria in 41 (14.7%), 38 (13.7%), and 13 (4.7%) studies, respectively.
Conclusions :
Hypotony failure criteria are highly heterogenous in current glaucoma literature, with few studies focusing on clinically relevant signs of hypotony. Further studies are warranted to examine the impact of different hypotony definitions on surgical success rates.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.