title: Circle- and grid-wise analyses of peripapillary nerve fiber layers by spectral domain optical coherence tomography in early-stage glaucoma.
abstract: OBJECTIVE
  To study diagnostic performances of circle- and grid-wise analyses of peripapillary retinal nerve fiber layer thickness (RNFLT) using spectral domain optical coherence tomography (SD-OCT) in early-stage glaucoma.
  
  
  METHODS
  Eighty-nine open-angle glaucoma (OAG) eyes (mean deviation: 2.5 ± 1.8 dB) and 89 age-matched normal eyes were studied. Peripapillary RNFLT was analyzed using an SD-OCT raster scan in a 6.0 × 6.0-mm area. Averaged RNFLT was calculated over 0.1 × 0.1-, 0.21 × 0.21-, or 0.42 × 0.42-mm grids in the peripapillary area (grid method), or arcuate sector areas between 2.8- and 4.0-mm diameter circles (annulus method), or along a 3.4-mm diameter circle (circle method). Normative data-based cutoff values for averaged RNFLT and number of abnormal grid locations (grid method) or sectors (annulus or circle method) were varied.
  
  
  RESULTS
  The grid method showed the best power of sensitivity/specificity of 0.94/0.96 with any five contiguous 0.21 × 0.21-mm grid locations with a 2.5 percentile cutoff, followed by the annulus method of 0.81/0.98, and the circle method of 0.76/0.97, with 30° sectors. The sensitivity of the grid method was significantly higher than that of the other methods (P < 0.001), whereas the specificity was not. Coefficients of variation and interclass correlation coefficients of intervisit measurements of averaged RNFLT over each 0.21 × 0.21-mm grid were 3.1% to 11.3% and 0.937 to 0.760, respectively, in a separate OAG patient group.
  
  
  CONCLUSIONS
  Grid-wise analyses of peripapillary RNFLT for differentiating early-stage glaucoma showed >0.90 sensitivity and ≥0.95 specificity.
authors.affiliation: Department of Ophthalmology, University of Tokyo Graduate School of Medicine, Tokyo, Japan. cmayama-tky@umin.ac.jp
authors.forename: Chihiro
authors.initials: C
authors.lastname: Mayama
authors.forename: Hitomi
authors.initials: H
authors.lastname: Saito
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Hirasawa
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Konno
authors.forename: Atsuo
authors.initials: A
authors.lastname: Tomidokoro
authors.forename: Makoto
authors.initials: M
authors.lastname: Araie
authors.forename: Aiko
authors.initials: A
authors.lastname: Iwase
authors.forename: Shinji
authors.initials: S
authors.lastname: Ohkubo
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Otani
authors.forename: Shoji
authors.initials: S
authors.lastname: Kishi
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsushita
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Maeda
authors.forename: Masanori
authors.initials: M
authors.lastname: Hangai
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: glaucoma; optic coherence tomography; retinal nerve fiber layer