title: Risk factors for adverse consequences of low intraocular pressure after trabeculectomy.
abstract: OBJECTIVE
  To determine the risk factors for low intraocular pressure (IOP) and its detrimental consequences after trabeculectomy.
  
  
  METHODS
  We performed a retrospective chart review of consecutive patients aged 12 years and above undergoing trabeculectomy alone by 1 of 2 surgeons between May 2000 and October 2008 at the Wilmer Institute.
  
  
  RESULTS
  Among 753 eyes of 596 patients, 112 eyes (14.9%) of 103 patients had an IOP of ≤5 mm Hg at ≥3 months postoperatively (late low IOP). Physical signs related to low IOP occurred in 61 eyes of 58 patients, and 40 eyes of 37 patients had revision surgery for low IOP. Physical signs of low IOP included 34 eyes with choroidal detachment or shallow anterior chamber, 10 with hypotony maculopathy, and 7 with both. Compared with 187 control eyes of 165 patients, risk factors for late low IOP included: surgeon 2 (P=0.0003), left eyes (P=0.03), and secondary glaucoma (P=0.05). Physical signs of low IOP were more common in phakic eyes (P=0.03), whereas need for revision surgery was associated with younger age (P=0.01). The presence of hypotony maculopathy significantly decreased the risk of choroidal detachment/shallow anterior chamber (P=0.003). Hypotony maculopathy was associated with younger age (P=0.02).
  
  
  CONCLUSIONS
  Late low IOP was more common with techniques used by 1 of 2 surgeons and in eyes with secondary glaucoma. Clinical signs of low IOP were more common in phakic eyes. Younger age was a risk factor for hypotony maculopathy. Hypotony maculopathy and choroidal detachment tend to occur in different eyes.
authors.affiliation: *Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine †Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD ‡Department of Pathology, Massachusetts General Hospital, Boston, MA and Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Osamah J
authors.initials: OJ
authors.lastname: Saeedi
authors.forename: Joan L
authors.initials: JL
authors.lastname: Jefferys
authors.forename: Jason F
authors.initials: JF
authors.lastname: Solus
authors.forename: Henry D
authors.initials: HD
authors.lastname: Jampel
authors.forename: Harry A
authors.initials: HA
authors.lastname: Quigley
mesh_terms: D000368:Aged; D000867:Anterior Chamber / Q000473:pathology; D015862:Choroid Diseases / Q000175:diagnosis / Q000209:etiology; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000601:surgery*; D005902:Glaucoma, Open-Angle / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D015814:Ocular Hypotension / Q000175:diagnosis / Q000209:etiology*; D011183:Postoperative Complications; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D014065:Tonometry, Ocular; D014130:Trabeculectomy