title: How often do patients need visual field tests?
abstract: BACKGROUND
  This study was undertaken to determine whether the interval between visual field tests affects the ability to detect progressive glaucomatous field loss.
  
  
  METHODS
  One hundred and nineteen retinal locations which were deteriorating significantly by > or = 1 dB/ year (untreated normal tension glaucoma patients: 6 eyes) were studied. Analysis was repeated using 'thinned' visual field tests: one test per year instead of the complete three per year over a period of 4 years.
  
  
  RESULTS
  The 'thinned' tests identified only 45.4% of the deteriorating points over the 4-year period. Furthermore, there was a mean delay of 1.10 years in detection (P < 0.01).
  
  
  CONCLUSIONS
  Less frequent visual field testing detects fewer progressing locations and detects them later.
authors.affiliation: Institute of Ophthalmology, London, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Viswanathan
authors.forename: R A
authors.initials: RA
authors.lastname: Hitchings
authors.forename: F W
authors.initials: FW
authors.lastname: Fitzke
mesh_terms: D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014787:Vision Tests; D014792:Visual Acuity; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields / Q000502:physiology