title: Canadian Glaucoma Study: 1. Study design, baseline characteristics, and preliminary analyses.
abstract: BACKGROUND
  The Canadian Glaucoma Study is a multicentered, prospective longitudinal study designed to study a variety of systemic risk factors for the progression of open-angle glaucoma under a standardised interventional protocol for intraocular pressure (IOP) control.
  
  
  METHODS
  Newly or previously diagnosed patients with early to moderate open-angle glaucoma were recruited consecutively from 5 hospital-based university departments. Baseline parameters, including an assessment of peripheral vasospasm, haematologic, coagulation, and immunopathologic variables were obtained. Newly diagnosed patients were targeted for a >or=30% reduction in IOP, whereas previously diagnosed patients entered the study at a physician-defined target IOP. After baseline examinations, patients were followed at 4-month intervals with standard automated perimetry, short-wavelength automated perimetry, and confocal scanning laser tomography, and at 28-32-month intervals with stereo disc photography. If the patient had visual field progression with standard automated perimetry, a further >or=20% reduction in IOP was mandated. A standardized IOP treatment protocol, ranging from topical monotherapy to filtration surgery, was implemented.
  
  
  RESULTS
  A total of 258 patients (131 [corrected] men and 127 [corrected] women, median age 65.0 years) were enrolled. Baseline median values for visual acuity, visual field mean deviation, untreated IOP, and refractive error were 0.10 logMAR, -4.04 dB, 25.0 mm Hg, and 0.00 D, respectively. Approximately 30% of the patients were hypertensive, 16% had cardiovascular disease, 9% thyroid disease, 9% diabetes, 14% migraine, and 19% were smokers. The median follow-up was 5.3 years, with 148 (57.0%) and 51 (19.8%) patients completing >or=5 and >or=7 years follow-up, respectively. The cumulative visual field progression rate at 2, 4, 6, and 8 years was 11.3%, 21.5%, 33.1%, and 43.5%, respectively.
  
  
  CONCLUSIONS
  We describe the study design and baseline patient characteristics of the Canadian Glaucoma Study and present some preliminary results. This long and close follow-up of a large group of patients will reveal the importance of several systemic factors for the progression of glaucoma.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Dalhousie University, Queen Elizabeth II Health Sciences Centre, Halifax, Novia Scotia, Canada. bal@dal.ca
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology; D003329:Coronary Vasospasm / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005385:Fingers / Q000098:blood supply; D005902:Glaucoma, Open-Angle / Q000188:drug therapy / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007429:Intraocular Pressure; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology; D009901:Optic Nerve Diseases / Q000503:physiopathology*; D011446:Prospective Studies; D012107:Research Design; D012307:Risk Factors; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields