title: Retrobulbar diversion of aqueous humor: clinical feasibility studies.
abstract: BACKGROUND
  The purpose of this study is to clinically evaluate a new form of glaucoma tube shunt drainage system. Tube shunts play an important role in management of advanced glaucoma, but eventually many blebs may become encapsulated and impervious to aqueous humor. This pilot study analyzed clinical efficacy of retrobulbar diversion of aqueous, either directly from anterior chamber (AC) or existing encapsulated blebs (EB), into the retrobulbar space (RS).
  
  
  METHODS
  Nineteen patients with intractable glaucoma underwent retrobulbar fenestrated implant surgery (16 with EB-to-RS and 3 AC-to-RS). Intraocular pressure, glaucoma medications, and acuity were assessed relative to preoperative baseline values by paired t test preoperatively and bimonthly up to 2 years. Preoperative and postoperative values were compared by paired t test.
  
  
  RESULTS
  Surgical patients (7 male, 12 female; mean, 62±3.3 y; progressive study entry; mean follow-up, 18.2 mo) maintained substantial intraocular pressure reduction, from preoperative mean 33.1±2.0 mm Hg to a sustained bimonthly mean of 14.6±1.6 mm Hg (14.6±1.1, 16.4±1.7, 13.9±1.2, 13.0±1.1, 13.3±2.0, 14.0±1.1, 12.2±2.2, 13.9±2.0, 15.1±1.4, 17.6±1.6, 15.6±2.0, and 16.0±1.6 at months 2 to 24, respectively; all P<0.00001). Acuity remained stable. Glaucoma medications were reduced from 2.8±0.3 to a bimonthly mean of 0.56±0.26 medications through 24 months (P<0.0001).
  
  
  CONCLUSIONS
  Retrobulbar shunts can divert aqueous from the AC into the RS, overcoming (through secondary EB-RS) and potentially obviating (through primary AC-RS) the ocular hypertension resulting from fibrotic plate encapsulation.
authors.affiliation: *UTSA Department of Biomedical Engineering, San Antonio, TX †University of Minnesota Medical School, Minneapolis, MN ‡Glaucoma Service, Department of Ophthalmology, Tulane University Medical Center, New Orleans, LA.
authors.forename: William E
authors.initials: WE
authors.lastname: Sponsel
authors.forename: Sylvia L
authors.initials: SL
authors.lastname: Groth
authors.forename: Ramesh S
authors.initials: RS
authors.lastname: Ayyala
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000601:surgery; D001082:Aqueous Humor / Q000502:physiology*; D001768:Blister / Q000601:surgery; D004322:Drainage; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000378:metabolism*; D010865:Pilot Projects; D019736:Prostheses and Implants; D012189:Retrospective Studies