title: Does Chronic Hypotony following Trabeculectomy Represent Treatment Failure?
abstract: OBJECTIVE
  To measure the rate of complications from chronic hypotony following trabeculectomy and clarify the definition of postoperative hypotony.
  
  
  METHODS
  In this retrospective case-control study, the rate of complications was compared between 34 eyes with chronic hypotony and 34 eyes without hypotony. Chronic hypotony was defined as those eyes with an intraocular pressure (IOP) of less than 6 mm Hg on two consecutive clinic visits at least 3 months after trabeculectomy. Cases were identified from a database of two glaucoma surgeons between 2010 and 2013. Outcomes measured included visual acuity, presence of choroidal effusion, hypotensive maculopathy and cataract development/progression. Factors associated with the development of hypotony were considered using analysis of variance (ANOVA) multivariate regression.
  
  
  RESULTS
  Maculopathy was seen in 23.5% of hypotony eyes but not in controls (p < 0.01). No significant difference in the rate of choroidal effusion or cataract was documented between groups. Control eyes were more likely to remain complication free (58.8 vs 32.4%, p < 0.03). Spontaneous recovery from hypotony occurred in 32.4% of hypotony eyes.
  
  
  CONCLUSIONS
  Sight threatening complications occur more frequently in eyes with chronic hypotony following glaucoma surgery. However, not all eyes with chronic hypotony develop sight threatening complications. A definition of hypotony that combines IOP criteria with the presence of structural and/or functional changes is recommended. How to cite this article: Yun S, Chua B, I Clement C. Does Chronic Hypotony following Trabeculectomy Represent Treatment Failure? J Curr Glaucoma Pract 2015;9(1):12-15.
authors.affiliation: Registrar, Glaucoma Unit, Sydney Eye Hospital, NSW 2000, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Yun
authors.affiliation: Staff Specialist, Senior Clinical LecturerGlaucoma Unit, Sydney Eye Hospital, NSW 2000, Australia; Central Clinical School, The University of Sydney, NSW Australia; School of Advanced Medicine, Macquarie University Sydney, Australia.
authors.forename: Brian
authors.initials: B
authors.lastname: Chua
authors.affiliation: Staff Specialist, Senior Clinical LecturerGlaucoma Unit, Sydney Eye Hospital, NSW 2000, Australia; Central Clinical School, The University of Sydney, NSW, Australia.
authors.forename: Colin I
authors.initials: CI
authors.lastname: Clement
keywords: Cataract.; Choroidal effusion; Filtration surgery; Glaucoma; Hypotensive maculopathy; Intraocular pressure