title: Reproducibility of Circumpapillary Retinal Nerve Fiber Layer Thickness Measurements Evaluated by Circle and Annulus Area With and Without Correction for Ocular Rotation.
abstract: OBJECTIVE
  To compare the reproducibility of annulus area measurements of the circumpapillary retinal nerve fiber layer thickness (cpRNFLTannulus) using spectral-domain optical coherence tomography (SD-OCT) with that of conventional cpRNFLT (cpRNFLTring) measurements and evaluate the effect of correction of ocular rotation on the reproducibility.
  
  
  METHODS
  Peripapillary SD-OCT raster scans were performed on 2 different days in 48 normal subjects and 59 patients with glaucoma using the Topcon OCT-1000. In the raster scan dataset, the cpRNFLTring and cpRNFLTannulus were averaged along a circle (3.4-mm diameter) and in an annulus area (diameters from 2.8 to 4.0 mm) centered on the barycenter of the disc. The measurement reproducibility, effects of ocular rotational correction, and factors affecting the reproducibility were studied.
  
  
  RESULTS
  The intervisit reproducibility values, expressed as the coefficients of variation, for the cpRNFLTannulus, were significantly smaller than those for the cpRNFLTring measurements in sectors 30 degrees wide in glaucomatous eyes (P=0.006) and in sectors 10 degrees wide in normal and glaucomatous eyes (P<0.001). The ocular rotational angles averaged 7.1 and 7.2 degrees with intervisit differences of 1.4 and 1.8 degrees, respectively, in normal and glaucomatous eyes. Correction for the ocular rotation had little effect on the reproducibility. The mean deviation and cpRNFLT were correlated negatively with the coefficient of variation (β=-0.93 to -0.83; P=0.027 to 0.028).
  
  
  CONCLUSIONS
  The cpRNFLTannulus measurement yielded better reproducibility than the cpRNFLTring measurement, and multiple linear regression analysis showed that the more advanced the glaucomatous damage, the worse the intervisit reproducibility.
authors.affiliation: *Department of Ophthalmology, University of Tokyo Graduate School of Medicine †Kanto Central Hospital of the Mutual Aid Association of Public School Teachers ‡Tomidokoro Eye Clinic, Tokyo §Tajimi Iwase Eye Clinic, Tajimi ∥Department of Ophthalmology and Visual Science, Kanazawa University Graduate School of Medical Science, Kanazawa ¶Department of Ophthalmology, Gunma University School of Medicine, Maebashi #Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka **Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Hirasawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Araie
authors.forename: Atsuo
authors.initials: A
authors.lastname: Tomidokoro
authors.forename: Aiko
authors.initials: A
authors.lastname: Iwase
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Shoji
authors.initials: S
authors.lastname: Kishi
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Maeda
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012399:Rotation; D041623:Tomography, Optical Coherence / Q000379:methods*; D014794:Visual Fields