title: Glaucoma monitoring in a clinical setting: glaucoma progression analysis vs nonparametric progression analysis in the Groningen Longitudinal Glaucoma Study.
abstract: OBJECTIVE
  To compare prospectively 2 perimetric progression detection algorithms for glaucoma, the Early Manifest Glaucoma Trial algorithm (glaucoma progression analysis [GPA]) and a nonparametric algorithm applied to the mean deviation (MD) (nonparametric progression analysis [NPA]).
  
  
  METHODS
  Patients with a reproducible glaucomatous visual field defect at baseline in at least 1 eye were followed up prospectively using perimetry (Humphrey field analyzer 30-2 Swedish interactive thresholding algorithm). Classifications by GPA and by NPA at the end of the follow-up period were compared.
  
  
  RESULTS
  Two hundred twenty-one patients met the inclusion criteria; 1 eye per patient was analyzed. On average, 7.1 reliable fields were available after a mean follow-up period of 5.3 years. The mean MD at baseline was -9.4 dB; the mean MD slope during the follow-up period was -0.25 dB/y. Fifty-six eyes showed progression by GPA and 89 eyes by NPA (P < .001); 42 eyes showed progression by both techniques (kappa = 0.39). In eyes with progression detected by NPA only, baseline MD was worse than that in eyes with progression detected by GPA (-12.5 vs -8.2 dB, P = .002), and GPA more often gave a reading of "baseline MD out of range" (P < .001). After exclusion of eyes with baseline MD out of range, the measure of agreement was kappa = 0.50.
  
  
  CONCLUSIONS
  Nonparametric progression analysis had fairly good agreement with GPA. Especially in cases of more advanced disease, NPA labeled more eyes as having progression than GPA.
authors.affiliation: Department of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Christiaan
authors.initials: C
authors.lastname: Wesselink
authors.forename: Govert P
authors.initials: GP
authors.lastname: Heeg
authors.forename: Nomdo M
authors.initials: NM
authors.lastname: Jansonius
mesh_terms: D000368:Aged; D000465:Algorithms; D001369:Axons / Q000473:pathology; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000473:pathology; D018709:Statistics, Nonparametric; D014786:Vision Disorders / Q000175:diagnosis / Q000503:physiopathology; D058609:Visual Field Tests / Q000379:methods; D014794:Visual Fields