title: A comparison of diagnostic protocols for interpretation of frequency doubling perimetry visual fields in glaucoma.
abstract: BACKGROUND
  Frequency doubling perimetry (FDP) shows good correlation with achromatic automated perimetry in the assessment of glaucoma. However, many recommended protocols lead to a significant number of false positives and negatives. Therefore, it may be difficult to identify visual field loss owing to glaucoma. We investigated the accuracy of a diagnostic protocol that only considered either temporal wedge, arcuate, or nasal step field loss on an FDP field as significant.
  
  
  METHODS
  Sixty-eight subjects who were glaucoma suspects, glaucoma patients or normal controls were recruited selectively. After achromatic automated perimetry and FDP visual field testing, results were compared between a conventional protocol and ones that took into account the position of FDP visual field loss.
  
  
  RESULTS
  If an FDP field was considered abnormal only when either a temporal wedge, an arcuate or a nasal step defect was present, the presence of a nasal step yielded the most accurate results with the least false positives (kappa coefficient=0.76) and with only minimal increase in false negatives, compared with a conventional FDP protocol (kappa coefficient=0.70).
  
  
  CONCLUSIONS
  Although, not statistically significant in this case, our results suggested a trend that a diagnostic protocol which considers nasal step FDP field loss significant may have a greater degree of accuracy when compared with conventional protocols and may facilitate interpretation in a clinical setting.
authors.affiliation: Eye Associates, Park House, Macquarie St, Adelaide, South Australia, Australia. john.landers@bigpond.com
authors.forename: John
authors.initials: J
authors.lastname: Landers
authors.forename: Alok
authors.initials: A
authors.lastname: Sharma
authors.forename: Ivan
authors.initials: I
authors.lastname: Goldberg
authors.forename: Stuart
authors.initials: S
authors.lastname: Graham
mesh_terms: D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields / Q000502:physiology*