title: Factors affecting the ability of the spectral domain optical coherence tomograph to detect photographic retinal nerve fiber layer defects.
abstract: OBJECTIVE
  To evaluate the ability of normative database classification (color-coded maps) of spectral domain optical coherence tomograph (SDOCT) in detecting wedge shaped retinal nerve fiber layer (RNFL) defects identified on photographs and the factors affecting the ability of SDOCT in detecting these RNFL defects.
  
  
  METHODS
  In a cross-sectional study, 238 eyes (476 RNFL quadrants) of 172 normal subjects and 85 eyes (103 RNFL quadrants with wedge shaped RNFL defects) of 66 glaucoma patients underwent RNFL imaging with SDOCT. Logistic regression models were used to evaluate the factors associated with false positive and false negative RNFL classifications of the color-coded maps of SDOCT.
  
  
  RESULTS
  False positive classification at a p value of <5% was seen in 108 of 476 quadrants (22.8%). False negative classification at a p value of <5% was seen in 16 of 103 quadrants (15.5%). Of the 103 quadrants with RNFL defects, 64 showed a corresponding VF defect in the opposite hemisphere and 39 were preperimetric. Higher signal strength index (SSI) of the scan was less likely to have a false positive classification (odds ratio: 0.97, p = 0.01). Presence of an associated visual field defect (odds ratio: 0.17, p = 0.01) and inferior quadrant RNFL defects as compared to superior (odds ratio: 0.24, p = 0.04) were less likely to show false negative classifications.
  
  
  CONCLUSIONS
  Scans with lower signal strengths were more likely to show false positive RNFL classifications, and preperimetric and superior quadrant RNFL defects were more likely to show false negative classifications on color-coded maps of SDOCT.
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: Uday K
authors.initials: UK
authors.lastname: Addepalli
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: 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; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*