title: Prospective study of ab externo erbium:YAG laser sclerostomy in humans.
abstract: OBJECTIVE
  To evaluate the efficacy of ab externo erbium:YAG (Er:YAG) laser sclerostomy in controlling intraocular pressure in eyes with uncontrolled glaucoma.
  
  
  METHODS
  We performed ab externo laser sclerostomy on eyes of 26 patients. Mean +/- SD postoperative follow-up was 11.4 +/- 0.9 months. Complete success was defined as intraocular pressure below 22 mm Hg with no adjunct medication; qualified success was defined as intraocular pressure below 22 mm Hg with medication.
  
  
  RESULTS
  In all eyes, ab externo Er:YAG laser sclerostomy achieved a functioning fistula with a prominent filtering bleb. Twelve eyes had had neodymium:YAG (Nd:YAG) laser iridotomy at the site of laser sclerostomy 2 weeks before filtering surgery; 14 eyes had surgical iridectomy at the site of laser sclerostomy. Mean preoperative intraocular pressure of 30.7 +/- 7.3 mm Hg (range, 17.0 to 48.0 mm Hg) was significantly (P < .05) reduced to 18.3 +/- 1.0 mm Hg (range, 0 to 25.0 mm Hg) at 2 weeks postoperatively. thereafter, marked regression was noted: at 1 month postoperatively, intraocular pressure was 20.1 +/- 9.5 mm Hg (range, 4.0 to 44.0 mm Hg); half-life of complete success was 25 days; of qualified success, 56 days; and of a functioning filtering bleb, 36 days.
  
  
  CONCLUSIONS
  Ab externo Er:YAG laser sclerostomy reliably created successful full-thickness fistulae with prominent filtering blebs in human glaucomatous eyes. However, a transient phase of ocular hypotony caused by aqueous overfiltration, followed by an ongoing rate of fistula patency failure, renders Er:YAG laser sclerostomy, as performed in this study, unsuitable for long-term pressure control.
authors.affiliation: Department of Ophthalmology, University of Cologne, Germany. Philipp.Jacobi@uni-koeln.de
authors.forename: P C
authors.initials: PC
authors.lastname: Jacobi
authors.forename: T S
authors.initials: TS
authors.lastname: Dietlein
authors.forename: G K
authors.initials: GK
authors.lastname: Krieglstein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D015812:Glaucoma, Angle-Closure / Q000473:pathology / Q000601:surgery*; D005902:Glaucoma, Open-Angle / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D053685:Laser Therapy; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011446:Prospective Studies; D012590:Sclera / Q000473:pathology / Q000601:surgery*; D012599:Sclerostomy / Q000379:methods*; D016896:Treatment Outcome