title: Clinical evaluation of a novel population-based regression analysis for detecting glaucomatous visual field progression.
abstract: BACKGROUND
  The distinction of real progression from test variability in visual field (VF) series may be based on clinical judgment, on trend analysis based on follow-up of test parameters over time, or on identification of a significant change related to the mean of baseline exams (event analysis). The aim of this study was to compare a new population-based method (Octopus field analysis, OFA) with classic regression analyses and clinical judgment for detecting glaucomatous VF changes.
  
  
  METHODS
  240 VF series of 240 patients with at least 9 consecutive examinations available were included into this study. They were independently classified by two experienced investigators. The results of such a classification served as a reference for comparison for the following statistical tests: (a) t-test global, (b) r-test global, (c) regression analysis of 10 VF clusters and (d) point-wise linear regression analysis.
  
  
  RESULTS
  32.5 % of the VF series were classified as progressive by the investigators. The sensitivity and specificity were 89.7 % and 92.0 % for r-test, and 73.1 % and 93.8 % for the t-test, respectively. In the point-wise linear regression analysis, the specificity was comparable (89.5 % versus 92 %), but the sensitivity was clearly lower than in the r-test (22.4 % versus 89.7 %) at a significance level of p = 0.01. A regression analysis for the 10 VF clusters showed a markedly higher sensitivity for the r-test (37.7 %) than the t-test (14.1 %) at a similar specificity (88.3 % versus 93.8 %) for a significant trend (p = 0.005). In regard to the cluster distribution, the paracentral clusters and the superior nasal hemifield progressed most frequently.
  
  
  CONCLUSIONS
  The population-based regression analysis seems to be superior to the trend analysis in detecting VF progression in glaucoma, and may eliminate the drawbacks of the event analysis. Further, it may assist the clinician in the evaluation of VF series and may allow better visualization of the correlation between function and structure owing to VF clusters.
authors.affiliation: Department of Ophthalmology, University Hospital of Basel, Basel, Switzerland. mgrieshaber@uhbs.ch
authors.forename: M P
authors.initials: MP
authors.lastname: Kovalska
authors.forename: E
authors.initials: E
authors.lastname: Bürki
authors.forename: A
authors.initials: A
authors.lastname: Schoetzau
authors.forename: S F
authors.initials: SF
authors.lastname: Orguel
authors.forename: S
authors.initials: S
authors.lastname: Orguel
authors.forename: M C
authors.initials: MC
authors.lastname: Grieshaber
mesh_terms: D000368:Aged; D003627:Data Interpretation, Statistical; D005260:Female; D005901:Glaucoma / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000175:diagnosis* / Q000209:etiology*; D058609:Visual Field Tests / Q000379:methods*