title: [Disc-fovea angle adjustment for peripallary retinal nerve fiber layer analysis by a spectral domain optical coherence tomography. Preliminary study].
abstract: BACKGROUND
  Circumpapillary retinal nerve fiber layer (cpRNFL) analysis by spectral domain optical coherence tomography (SD-OCT) has become essential for the assessment of glaucoma patients. The foveal projection is conventionally below the disc plane, creating an angle with the horizontal meridian, the disc-fovea angle. The purpose of this study is to evaluate the role of adjustment of cpRNFL analysis based on this angle.
  
  
  METHODS
  This study concerns 40 control eyes and 55 eyes affected with and followed for primary open angle glaucoma (POAG). After precise localization of the optic disc center and the axis connecting it to the center of the fovea, a circular peripapillary scan is performed with Spectralis OCT (Heidelberg Engineering, Germany). The mean thickness in each of six papillary sectors and the global mean thickness of the cpRNFL were evaluated. The ROC (receiver operating characteristic) analysis evaluated the diagnostic capabilities of the various sectors before and after adjustment of the analysis for the disc-fovea angle.
  
  
  RESULTS
  The disc-fovea angle was not different between the two groups (-7.0 ± 1.2° for controls vs. -6.6 ± 1.2° for POAG, P=0.70). There is a significant variance of this angle in both groups (the angle varies in the control group between -22.5° to +1.8° and in the POAG group between -18° to +2.4°). The global mean and inferior temporal (IT) thickness of the cpRNFL show the best diagnostic performance. Adjustment for disc-fovea angle does not increase the diagnostic accuracy of the various sectors analyzed. Although there is an increase in the area under the curve for the IT sector after adjustment, it is not statistically significant (0.910 ± 0.056 vs. 0.936 ± 0.045, P=0.06).
  
  
  CONCLUSIONS
  There is a significant variation in disc-fovea angle. In this study, accounting for it does not significantly improve the diagnostic capabilities of cpRNFL in patients with POAG.
authors: Service d'ophtalmologie, HIA Desgenettes, 108, boulevard Pinel, 69003 Lyon, France. Electronic address: elchehab_hussam@hotmail.fr.
authors: H
authors: H
authors: El Chehab
authors: Service d'ophtalmologie, HIA Desgenettes, 108, boulevard Pinel, 69003 Lyon, France.
authors: C
authors: C
authors: Dot
authors: Service d'ophtalmologie, HIA Val-de-Grâce, 74, boulevard Port-Royal, 75005 Paris, France.
authors: J-P
authors: JP
authors: Renard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002138:Calibration; D016022:Case-Control Studies; D005260:Female; D005584:Fovea Centralis / Q000000981:diagnostic imaging* / Q000473:pathology; D005902:Glaucoma, Open-Angle / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000000981:diagnostic imaging* / Q000473:pathology; D010865:Pilot Projects; D012160:Retina / Q000166:cytology / Q000000981:diagnostic imaging* / Q000473:pathology; D055351:Retinal Neurons / Q000166:cytology / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000379:methods* / Q000592:standards; D014794:Visual Fields
keywords: Angle papillo-maculaire; Circumpapillary retinal nerve fiber layer; Disc-fovea angle; Fibres nerveuses rétiniennes péripapillaires; Glaucome primitif à angle ouvert; Optical coherence tomography; Primary open angle glaucoma; Tomographie à cohérence optique