title: Semiautomated quantification of β-zone parapapillary atrophy using blue light fundus autofluorescence.
abstract: OBJECTIVE
  To evaluate the reproducibility of measurements of area of β-zone parapapillary atrophy (β-PPA) using blue laser fundus autofluorescence (FAF) and confocal scanning laser ophthalmoscopy reflectance (CSLO) measurements and to assess agreement between the two imaging modalities.
  
  
  METHODS
  Sixty-five eyes of 45 patients (mean age, 68.2 ± 11.3 years) with established or suspected glaucoma from the Diagnostic Innovations in Glaucoma Study (DIGS) were prospectively included. FAF scans were obtained with the Spectralis HRA+OCT and CSLO reflectance images with the HRTII (both from Heidelberg Engineering, Heidelberg, Germany). Two masked graders independently measured β-PPA area on 3 consecutive scans using the semi-automated BluePeak RegionFinder software (BPRF) and on CSLO reflectance images using the optic disc contour line. Reproducibility of β-PPA area measurements was assessed using intraclass correlation coefficients (ICC).
  
  
  RESULTS
  Intragrader reproducibility was 0.997 (95% CI, 0.996-0.998) and 0.995 (95% CI, 0.992-0.996) for grader 1 and 2, respectively, using FAF-BPRF, and by CSLO, it was 0.991 (95% CI, 0.986-0.994) and 0.988 (95% CI, 0.982-0.992). Intergrader agreement (ICC) was 0.53 (95% CI, 0.331-0.685) for FAF-BPRF and 0.404 (95% CI, 0.149-0.601) for CSLO (comparison between ICC, p = 0.368). Agreement (ICC) between the two devices was worse for grader 1 (0.356; 95% CI, 0.129-0.549) than grader 2 (0.856; 95% CI, 0.774-0.910) (p < 0.001).
  
  
  CONCLUSIONS
  Despite excellent intragrader reproducibility for β-PPA measurements with FAF-BPRF and CSLO, intergrader reproducibility is low to moderate. Measurements of β-PPA area obtained with the two instruments are of moderate agreement and, therefore, are not interchangeable.
authors.affiliation: Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, CA, USA.
authors.forename: Kaweh
authors.initials: K
authors.lastname: Mansouri
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Tung
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Medeiros
authors.forename: Ali
authors.initials: A
authors.lastname: Tafreshi
authors.forename: Syril
authors.initials: S
authors.lastname: Dorairaj
authors.forename: Linda
authors.initials: L
authors.lastname: Zangwill
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.forename: Sonia
authors.initials: S
authors.lastname: Jain
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis; D009887:Ophthalmoscopy / Q000379:methods*; D009896:Optic Atrophy / Q000175:diagnosis* / Q000209:etiology; D009898:Optic Disk / Q000473:pathology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: blue-peak autofluorescence; glaucoma; parapapillary atrophy; β-zone