title: Pointwise linear regression for evaluation of visual field outcomes and comparison with the advanced glaucoma intervention study methods.
abstract: OBJECTIVE
  To investigate pointwise linear regression (PLR) for longitudinal evaluation of visual fields and to compare results with those of the Advanced Glaucoma Intervention Study (AGIS) criteria.
  
  
  METHODS
  We selected 509 eyes (401 patients) from the AGIS with 3 or more years of follow-up, 7 or more visual field examinations, and an AGIS reference score of 16 or lower. Visual field change at test locations was defined as a change of threshold sensitivity of 1 dB/y or higher and P<or=.01. Several sets of criteria were investigated for defining change of visual field series with PLR.
  
  
  METHODS
  Progression or improvement of visual field series with PLR and AGIS criteria.
  
  
  RESULTS
  Mean (SD) follow-up time and baseline AGIS score were 7.4 (1.7) years and 7.7 (4.4), respectively. Pairwise agreement between AGIS and various PLR criteria ranged from 52% to 64% with the kappa statistic varying between 0.22 (95% confidence interval, 0.15-0.29) and 0.30 (95% confidence interval, 0.22-0.38). One hundred thirty-eight (27%) and 151 (30%) eyes progressed (85 eyes or 17% detected by both methods) while 72 (14%) and 11 (2%) eyes improved (5 eyes or 1% detected by both methods) based on AGIS and the most rigorous PLR criteria, respectively.
  
  
  CONCLUSIONS
  Based on rigorous, clinically relevant criteria, PLR detects progression in a similar proportion of eyes compared with AGIS criteria. Pointwise linear regression may be superior to AGIS methods since it identifies fewer visual field series as improving.
authors.affiliation: Glaucoma Division, Jules Stein Eye Institute, University of California Los Angeles, 90095-7004, USA.
authors.forename: Kouros
authors.initials: K
authors.lastname: Nouri-Mahdavi
authors.forename: Joseph
authors.initials: J
authors.lastname: Caprioli
authors.forename: Anne L
authors.initials: AL
authors.lastname: Coleman
authors.forename: Douglas
authors.initials: D
authors.lastname: Hoffman
authors.forename: Douglas
authors.initials: D
authors.lastname: Gaasterland
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000503:physiopathology; D016032:Randomized Controlled Trials as Topic; D012684:Sensory Thresholds; D014130:Trabeculectomy; D014786:Vision Disorders / Q000175:diagnosis* / Q000503:physiopathology; D014794:Visual Fields