title: Frequency-doubling technology: searching for the optimum diagnostic criteria for glaucoma.
abstract: OBJECTIVE
  To determine the diagnostic criteria of perimetry using frequency-doubling technology (FDT) with the best possible sensitivity-specificity balance for glaucoma diagnosis.
  
  
  METHODS
  A total of 92 healthy control subjects and 110 patients with varying degrees of glaucomatous visual field loss on standard automated perimetry (SAP) were used to obtain the best diagnostic criterion for the disease, by using screening C-20-1 and threshold C-20 strategies from original FDT perimetry. Another prospective sample of 52 normal eyes and 64 glaucoma eyes was used to test how well this optimum criterion performs in other populations. Receiver operating characteristic (ROC) curves were plotted for the number of altered points at each level of probability for the C-20-1 and threshold C-20 modes. In addition, ROC curves were calculated for the global indices of the threshold C-20 strategy.
  
  
  RESULTS
  The best criterion for the C-20-1 strategy is the presence of one or more altered points with p < 1% (57.81% sensitivity and 100% specificity). The optimum criteria for glaucoma diagnosis for the threshold C-20 strategy are the presence of five or more altered points with p < 5% and/or two or more altered points with p < 2% and/or at least one altered point with p < 1% at any location (79.68% sensitivity and 94.2% specificity).
  
  
  CONCLUSIONS
  By using the C-20-1 strategy, a p < 1% defect anywhere showed 100% specificity with the lowest test duration. The criteria proposed for the threshold C-20 algorithm presented a good sensitivity-specificity balance. The threshold C-20 test provides higher sensitivity than the C-20-1 strategy but takes about five times longer to perform.
authors.affiliation: Department of Ophthalmology, Miguel Servet University Hospital, Zaragoza, Spain. aferreras@msn.com
authors.forename: Antonio
authors.initials: A
authors.lastname: Ferreras
authors.forename: José M
authors.initials: JM
authors.lastname: Larrosa
authors.forename: Vicente
authors.initials: V
authors.lastname: Polo
authors.forename: Ana B
authors.initials: AB
authors.lastname: Pajarín
authors.forename: Francesca
authors.initials: F
authors.lastname: Mayoral
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Honrubia
mesh_terms: D005189:False Positive Reactions; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000175:diagnosis*; D058609:Visual Field Tests / Q000592:standards*; D014794:Visual Fields