title: Role of visual field reliability indices in ruling out glaucoma.
abstract: OBJECTIVE
  Standard automated perimetry is the current criterion standard for assessment of visual field (VF) loss in glaucoma. The 3 commonly used reliability indices to judge the quality of standard automated perimetry results are fixation losses (FLs) and false-positive (FP) and false-negative (FN) response rates. However, the influence of reliability indices, when within the manufacturer-recommended limits, on VF classification has been sparsely studied.
  
  
  OBJECTIVE
  To evaluate the role of VF reliability indices in ruling out glaucoma.
  
  
  METHODS
  A cross-sectional study of 291 eyes of 291 participants referred to a tertiary eye care facility by general ophthalmologists. The participants were suspected to have glaucoma based on optic disc appearance, but the eyes were judged to be normal with physiological cupping by glaucoma experts on masked evaluation of optic disc photographs. All participants underwent VF testing with the Swedish interactive threshold algorithm standard 24-2 program.
  
  
  METHODS
  Logistic regression models were used to evaluate the associations between reliability indices and FP classifications on VF testing (glaucoma hemifield test as outside normal limits and pattern standard deviation with P < .05).
  
  
  RESULTS
  Median FL, FP, and FN response rates were 7%, 1%, and 2%, respectively. Among the 241 participants with reliable VF results (FL <20% and FP response rate <15%), the VF classification was normal in 188 (78.0%) and glaucoma (FP) in 53 (22.0%). Probability of FP VF classification was associated with FN response rates (odds ratio [OR], 1.36; 95% CI, 1.25-1.48, P < .001) but did not appear to be associated with FLs (OR, 0.96; 95% CI, 0.90-1.03, P = .30) or FP response rates (OR, 0.96; 95% CI, 0.83-1.12, P = .64). Predicted probability of FP VF classification was 9% (95% CI, 6%-14%), 40% (32%-49%), and 82% (68%-91%) at FN response rates of 0%, 8%, and 16%, respectively.
  
  
  CONCLUSIONS
  This study suggests that FN response rates have an effect on the ability of automated VF assessments to rule out glaucoma. Since FN response rates are ignored by the manufacturer while flagging a test as unreliable, clinicians and researchers may benefit by realizing that FN response rates can lead to FP VF classification, even when their frequencies are small.
authors.affiliation: VST Glaucoma Center, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Harsha L
authors.initials: HL
authors.lastname: Rao
authors.affiliation: VST Glaucoma Center, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Yadav
authors.affiliation: VST Glaucoma Center, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Viquar U
authors.initials: VU
authors.lastname: Begum
authors.affiliation: VST Glaucoma Center, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Uday K
authors.initials: UK
authors.lastname: Addepalli
authors.affiliation: VST Glaucoma Center, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Nikhil S
authors.initials: NS
authors.lastname: Choudhari
authors.affiliation: VST Glaucoma Center, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Sirisha
authors.initials: S
authors.lastname: Senthil
authors.affiliation: VST Glaucoma Center, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Chandra S
authors.initials: CS
authors.lastname: Garudadri
mesh_terms: D000328:Adult; D000465:Algorithms; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006305:Health Status Indicators; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014065:Tonometry, Ocular; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests / Q000592:standards*; D014794:Visual Fields