title: Agreement between event-based and trend-based glaucoma progression analyses.
abstract: OBJECTIVE
  To evaluate the agreement between event- and trend-based analyses to determine visual field (VF) progression in glaucoma.
  
  
  METHODS
  VFs of 175 glaucoma eyes with ≥5 VFs were analyzed by proprietary software of VF analyzer to determine progression. Agreement (κ) between trend-based analysis of VF index (VFI) and event-based analysis (glaucoma progression analysis, GPA) was evaluated. For eyes progressing by event- and trend-based methods, time to progression by two methods was calculated.
  
  
  RESULTS
  Median number of VFs per eye was 7 and follow-up 7.5 years. GPA classified 101 eyes (57.7%) as stable, 30 eyes (17.1%) as possible and 44 eyes (25.2%) as likely progression. Trend-based analysis classified 122 eyes (69.7%) as stable (slope >-1% per year or any slope magnitude with P>0.05), 53 eyes (30.3%) as progressing with slope <-1% per year, P≤0.05 (sensitive criteria), and 37 eyes (21.1%) as progressing with slope <-1% per year, P≤0.01 (specific criteria). κ between sensitive criteria of GPA (possible combined with likely progression) and trend-based analysis was 0.48, and between specific criteria of GPA (possible clubbed with no progression) and trend-based analysis was 0.50. In eyes progressing by sensitive criteria of both methods (42 eyes), median time to progression by GPA (4.9 years) was similar (P=0.30) to trend-based method (5.0 years). This was also similar in eyes progressing by specific criteria of both methods (25 eyes; 5.6 years versus 5.9 years, P=0.23).
  
  
  CONCLUSIONS
  Agreement between event- and trend-based progression analysis was moderate. GPA seemed to detect progression earlier than trend-based analysis, but this wasn't statistically significant.
authors.affiliation: VST Glaucoma Center, L V Prasad Eye Institute, Hyderabad, India. harshalaxmanarao@gmail.com
authors.forename: H L
authors.initials: HL
authors.lastname: Rao
authors.forename: T
authors.initials: T
authors.lastname: Kumbar
authors.forename: A U
authors.initials: AU
authors.lastname: Kumar
authors.forename: J G
authors.initials: JG
authors.lastname: Babu
authors.forename: S
authors.initials: S
authors.lastname: Senthil
authors.forename: C S
authors.initials: CS
authors.lastname: Garudadri
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult