title: Clinical decision making based on data from GDx: one-year observations.
abstract: OBJECTIVE
  To determine whether information derived from the GDx scanning laser polarimeter aids in the clinical decision-making process for patients with various types of glaucoma.
  
  
  METHODS
  Over a 4-month period, 342 consecutive patients with primary open-angle glaucoma, ocular hypertension, angle-closure glaucoma, or secondary glaucomas or in whom the diagnosis of glaucoma was uncertain were evaluated with the GDx scanning laser. After 1 year, 153 patients with glaucoma underwent GDx analysis again. Chart review revealed that 42 of the 153 patients had a change in therapy as a result of the GDx evaluation combined with analysis of visual fields, optic disc cupping, and intraocular pressure (IOP). Outcomes were then compared.
  
  
  RESULTS
  The group who had a change in therapy had a higher average GDx number (51.5 +/- 26.1 vs 37.0 +/- 23.5 [P = .001]) at the initial visit and higher IOP (18.2 +/- 4.6 vs 16.0 +/- 3.2 mm Hg [P = .005]). In spite of a change in therapy, at an average of 344 days later, IOP was unchanged (18.3 +/- 5.3 vs 15.7 +/- 3.2 mm Hg [P = .001]) and GDx values in the altered therapy group were higher than at baseline (57.3 +/- 27.9 vs 36.7 +/- 23.4 [P = .001]), although the differences within each group did not achieve statistical significance.
  
  
  CONCLUSIONS
  GDx analysis may be helpful in determining patients at risk for damage from glaucoma, even in eyes in which cup-disc ratio and field loss have not progressed. Changing medications without significantly reducing IOP may be insufficient to halt increases in GDx numbers and may indicate a need for more aggressive therapy.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, Missouri, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Bobrow
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001718:Birefringence; D003657:Decision Making; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure; D007834:Lasers; D008297:Male; D009412:Nerve Fibers / Q000473:pathology*; D009798:Ocular Hypertension / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D014786:Vision Disorders / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D014794:Visual Fields
chemical_list: D000959:Antihypertensive Agents