title: Validation of test duration as a screening criterion for frequency doubling perimetry.
abstract: OBJECTIVE
  To validate the test duration in frequency doubling perimetry as an independent criterion to screen for glaucomatous field defects.
  
  
  METHODS
  Prospective cross-sectional study
  
  
  METHODS
  Group I included 85 eyes (85 patients) with established field defects on automated perimetry. Group II comprised 41 normal eyes (41 subjects). Both groups underwent Swedish interactive testing algorithm standard tests as well as frequency doubling perimetry (C20-1). A cutoff level of 90 seconds was used to calculate test duration sensitivity and specificity. We also categorized patients into those who took <=90 seconds or less and those who took >90 seconds to complete the test and compared frequency doubling perimetry (any two abnormal points) with Swedish interactive testing algorithm in these groups.
  
  
  RESULTS
  Duration of the test >90 seconds had 97.5% specificity with 62.3% sensitivity. Eleven subjects with glaucoma completed test in <91 seconds).
  
  
  CONCLUSIONS
  Test duration alone has a limited value in screening for glaucoma.
authors.affiliation: L.V. Prasad Eye Institute, Banjara Hills, Hyderabad, India. ravithomas@lvpeye.stph.net
authors.forename: Ravi
authors.initials: R
authors.lastname: Thomas
authors.forename: Rajul
authors.initials: R
authors.lastname: Parikh
authors.forename: Jayaprakash
authors.initials: J
authors.lastname: Muliyil
authors.forename: Savita
authors.initials: S
authors.lastname: Bhat
authors.forename: Ronnie
authors.initials: R
authors.lastname: George
mesh_terms: D000465:Algorithms; D003430:Cross-Sectional Studies; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D014786:Vision Disorders / Q000175:diagnosis*; D014792:Visual Acuity; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields