title: Rates of progressive retinal nerve fiber layer loss in glaucoma measured by scanning laser polarimetry.
abstract: OBJECTIVE
  To evaluate rates of change measured with scanning laser polarimetry with enhanced corneal compensation (GDx ECC) and compare them to those measured using the variable corneal compensation (GDx VCC) method in a cohort of glaucoma patients and individuals suspected of having the disease followed over time.
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  The study included 213 eyes of 213 patients with an average follow-up time of 4.5 years. Images were obtained annually with the GDx ECC and VCC, along with optic disc stereophotographs and standard automated perimetry (SAP) visual fields. Progression was determined by the Guided Progression Analysis software for SAP and by masked assessment of stereophotographs by expert graders. Joint linear mixed-effects models were used to evaluate rates of change in GDx measurements and their relationship with disease progression.
  
  
  RESULTS
  Thirty-three patients (15%) showed progression over time on visual fields and/or stereophotographs. Mean rates of average retinal nerve fiber layer (RNFL) thickness change measured by the GDx ECC were significantly different in progressors versus nonprogressors (-1.24 microm/year vs -0.34 microm/year; P < .001). The area under the ROC curve for discriminating progressors from nonprogressors was significantly higher for rates of change measured by ECC compared to VCC (0.89 vs 0.65; P < .001).
  
  
  CONCLUSIONS
  Rates of RNFL change detected by the GDx ECC were significantly greater in eyes with progressive glaucoma compared to eyes with stable disease. Also, the ECC performed significantly better than the VCC for detection of change, suggesting that it could improve longitudinal evaluation of the RNFL with scanning laser polarimetry.
authors.affiliation: Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, San Diego, California, USA. fmedeiros@eyecenter.ucsd.edu
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Medeiros
authors.forename: Linda M
authors.initials: LM
authors.lastname: Zangwill
authors.forename: Luciana M
authors.initials: LM
authors.lastname: Alencar
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Sample
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
mesh_terms: D019540:Area Under Curve; D001718:Birefringence; D015331:Cohort Studies; D003315:Cornea / Q000502:physiology; D018450:Disease Progression; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000503:physiopathology; D012372:ROC Curve; D012165:Retinal Ganglion Cells / Q000473:pathology*; D057109:Scanning Laser Polarimetry; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology