title: Topographic correlation between β-zone parapapillary atrophy and retinal nerve fiber layer defect.
abstract: OBJECTIVE
  To investigate whether a topographic correlation exists between β-zone parapapillary atrophy (PPA) and retinal nerve fiber layer (RNFL) defect. The location and extent of the β-zone were examined.
  
  
  METHODS
  Retrospective, cross-sectional study.
  
  
  METHODS
  One hundred twenty-eight eyes from 128 consecutive patients with primary open-angle glaucoma (POAG) and a single localized RNFL defect were included.
  
  
  METHODS
  Digital optic disc photographs of the enrolled eyes were reviewed and eyes with β-zone PPA were identified. The topographic parameters of β-zone PPA and RNFL defect were measured on optic disc photographs and digital red-free RNFL photographs. The association between these parameters was examined statistically.
  
  
  METHODS
  Angular location and angular extent of β-zone PPA and RNFL defect, angular location of point of maximum radial extent (PMRE) of β-zone PPA, and β-zone PPA-to-disc area ratio.
  
  
  RESULTS
  Eighty-two (64.1%) of the 128 eyes with a single localized RNFL defect had β-zone PPA. Patients with β-zone PPA were younger (by 6.6 years) than those without β-zone PPA (P = 0.001). β-Zone PPA was located most commonly inferotemporally (65.9%). The RNFL defect was located in the same hemifield as the β-zone PPA in 76% of eyes and was located in the same hemifield as PMRE in 88% of eyes. The angular location of the RNFL defect showed a linear correlation with those of β-zone PPA (r = 0.390; P<0.001) and PMRE (r = 0.558; P<0.001). The angular extent of RNFL defect was not correlated significantly with that of β-zone PPA (P = 0.106), but it was associated weakly with β-zone PPA-to-disc area ratio (r = 0.197; P = 0.026). The angular extent of the RNFL defect also was correlated with the cup-to-disc ratio (r = 0.322; P<0.001) and the cup-to-disc area ratio (r = 0.337; P = 0.002).
  
  
  CONCLUSIONS
  In POAG, a localized RNFL defect is correlated spatially with β-zone PPA.
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea; Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Bum-Joo
authors.initials: BJ
authors.lastname: Cho
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea; Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea. Electronic address: kihopark@snu.ac.kr.
authors.forename: Ki Ho
authors.initials: KH
authors.lastname: Park
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009896:Optic Atrophy / Q000175:diagnosis*; D009898:Optic Disk / Q000473:pathology*; D010781:Photography; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012189:Retrospective Studies; D012607:Scotoma / Q000175:diagnosis; D019371:Topography, Medical; D014794:Visual Fields