title: Ibopamine challenge test can be used to differentiate glaucoma suspects from glaucoma patients.
abstract: BACKGROUND
  Many countries face the challenge of a rising number of patients with or at risk of developing glaucoma. A test to differentiate between people who are unlikely to develop glaucoma and those at risk for the disease could be clinically useful. Ibopamine, when administered topically, temporarily increases aqueous production. Normal eyes with healthy trabecular meshwork show no significant change in intraocular pressure (IOP) following an ibopamine challenge; however, those with glaucoma demonstrate elevated IOP.
  
  
  METHODS
  The study was designed as a prospective case-control study in a tertiary hospital.
  
  
  METHODS
  Patients were recruited consecutively as they presented to glaucoma clinics at Flinders Medical Centre (n = 39); the sample included 18 glaucoma suspects and 21 patients with glaucoma. All patients had open anterior chamber angles and no evidence of secondary glaucoma.
  
  
  METHODS
  Patients underwent IOP measurements followed by instillation of ibopamine 2% solution and subsequent repeated IOP assessment. The difference between the baseline measurement and that taken at 45 min was determined and compared between groups.
  
  
  METHODS
  The outcome measure was the positivity of the ibopamine challenge test, defined by an increase in IOP > 3 mmHg.
  
  
  RESULTS
  We observed a mean increase in IOP of 1.9 ± 1.6 mmHg or 12.5 ± 10.3%) for glaucoma suspects and 7.4 ± 4 mmHg or 52.4 ± 26.5% for glaucoma patients (P < 0.0001). Four glaucoma suspects (22%) and 19 glaucoma patients (90%) tested positive (P < 0.0001).
  
  
  CONCLUSIONS
  This study demonstrates that ibopamine has potential as a test to differentiate glaucoma suspects from patients with glaucoma.
authors.affiliation: Department of Ophthalmology, Flinders Medical Centre, Adelaide, South Australia, Australia.
authors.forename: Katja
authors.initials: K
authors.lastname: Ullrich
authors.forename: Jamie E
authors.initials: JE
authors.lastname: Craig
authors.forename: John
authors.initials: J
authors.lastname: Landers
mesh_terms: D000287:Administration, Topical; D000368:Aged; D016022:Case-Control Studies; D003846:Deoxyepinephrine / Q000031:analogs & derivatives*; D018491:Dopamine Agonists; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D009184:Mydriatics; D009798:Ocular Hypertension / Q000175:diagnosis*; D009883:Ophthalmic Solutions; D011446:Prospective Studies
chemical_list: D018491:Dopamine Agonists; D009184:Mydriatics; D009883:Ophthalmic Solutions; C023487:ibopamine; D003846:Deoxyepinephrine
keywords: challenge test; glaucoma; ibopamine; open-angle glaucoma; preventive medicine