title: Efficacy of Additional Glaucoma Drainage Device Insertion in Refractory Glaucoma: Case Series with a Systematic Literature Review and Meta-Analysis.
abstract: OBJECTIVE
  To report the efficacy of additional glaucoma drainage device (GDD) insertion in eyes with refractory glaucoma and which have a failed primary GDD.
  
  
  METHODS
  We conducted a non-comparative, retrospective study on eight eyes of eight patients who had a failed primary GDD and received an additional GDD in the same eye. Intraocular pressure (IOP), visual acuity (VA), the number of anti-glaucomatous medications, and complications were analyzed during the most recent office visit. Success was defined as an IOP between 6 and 21 mmHg and a 20% decrease in IOP after additional GDD insertion, with or without anti-glaucomatous medication.
  
  
  RESULTS
  The mean decrease in IOP at the final follow-up was 19.3 mmHg (56.1%). The mean number of anti-glaucomatous medications used at the final follow-up (2.38) was significantly less than the preoperative mean (3.50). Seven patients achieved the criteria for success, whereas one patient had an unsuccessful outcome because of corneal graft failure after additional GDD insertion.
  
  
  CONCLUSIONS
  We showed that after the failure of a primary GDD, an additional GDD offered favorable IOP control and stable VA. In agreement with a review of previous literature, GDD insertion is the best option for treating refractory glaucoma, even in patients with a failed primary GDD.
authors.affiliation: a Department of Ophthalmology and Visual Science , Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul , Korea .
authors.forename: Na Young
authors.initials: NY
authors.lastname: Lee
authors.affiliation: b Department of Ophthalmology and Visual Science , Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul , Korea , and.
authors.forename: Hyung Bin
authors.initials: HB
authors.lastname: Hwang
authors.affiliation: a Department of Ophthalmology and Visual Science , Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul , Korea .
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Oh
authors.affiliation: c Department of Ophthalmology and Visual Science , Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul , Korea.
authors.forename: Chan Kee
authors.initials: CK
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D005901:Glaucoma / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D019919:Prosthesis Implantation; D017211:Treatment Failure; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology
keywords: Glaucoma drainage device; intraocular pressure; refractory glaucoma