title: Early detection of visual field progression in glaucoma: a comparison of PROGRESSOR and STATPAC 2.
abstract: OBJECTIVE
  To compare the performance of PROGRESSOR (pointwise linear regression) and STATPAC 2 (comparison with baseline values) in detecting early deterioration in the visual fields of glaucoma patients.
  
  
  METHODS
  Visual field series from 19 untreated normal tension glaucoma eyes which were deteriorating on clinical grounds were analysed by PROGRESSOR and STATPAC 2. Progression criteria for PROGRESSOR were (1) inner points: slope < -1 dB/year, p < 0.05 and (2) edge points: slope < -2 dB/year, p < 0.05. Criteria for STATPAC 2 were p < 0.05 change probability for any point on three consecutive fields. Detection time was defined as the time interval between the initial field and the first field in which at least one progressing point was identified. Detection times produced by the two techniques were compared.
  
  
  RESULTS
  PROGRESSOR and STATPAC 2 agreed on progression in all 19 eyes. Mean detection time for PROGRESSOR was 1.077 (SD 0.985) years and for STATPAC 2 was 2.161 (1.357) years. PROGRESSOR detected progression sooner than STATPAC 2 in 18 eyes (p < 0.01), Wilcoxon matched pairs signed rank test). PROGRESSOR detected progression earlier by a mean of 1.085 (0.936) years.
  
  
  CONCLUSIONS
  PROGRESSOR consistently detected progression earlier than STATPAC 2. The PROGRESSOR software is a useful tool for the early detection of visual field deterioration in glaucoma.
authors.affiliation: Institute of Ophthalmology, London.
authors.forename: A C
authors.initials: AC
authors.lastname: Viswanathan
authors.forename: F W
authors.initials: FW
authors.lastname: Fitzke
authors.forename: R A
authors.initials: RA
authors.lastname: Hitchings
mesh_terms: D000465:Algorithms; D003196:Computer Graphics; D018450:Disease Progression; D005500:Follow-Up Studies; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D012984:Software; D013997:Time Factors; D058609:Visual Field Tests; D014794:Visual Fields