title: Intereye Difference in the Microstructure of Parapapillary Atrophy in Unilateral Primary Open-Angle Glaucoma.
abstract: OBJECTIVE
  To investigate intereye differences in the parapapillary atrophy (PPA) microstructure in unilateral primary open-angle glaucoma (POAG).
  
  
  METHODS
  Bilateral optic nerves from 172 unilateral POAG patients having clinical PPA shown in infrared fundus imaging were scanned using spectral-domain optical coherence tomography (SD-OCT). Based on the extent of Bruch's membrane (BM) within the PPA area, the PPA was divided into β-zone (area with BM) and γ-zone (area devoid of BM). The width of each type of PPA and disc tilt angle were measured in radial B-scan images. Disc tilt ratio and torsion degree were determined using the radial B-scan and infrared fundus images. Measurements were compared between the glaucomatous and contralateral healthy eyes, and the factors associated with the presence of glaucoma were determined.
  
  
  RESULTS
  The width of β-zone was larger in glaucomatous eyes compared with the contralateral healthy eyes (283.67 ± 157.45 vs. 214.42 ± 145.39 μm, P < 0.001), whereas there were no significant intereye differences in the γ-zone width (P = 0.392). Eyes with POAG had a larger β-zone width (P < 0.001), and larger tilt angle (P = 0.032) compared with the contralateral healthy eyes. In multivariate regression analysis, larger β-zone width (P < 0.001), and lower IOP (P = 0.001) were revealed as significant factors associated with the presence of glaucoma.
  
  
  CONCLUSIONS
  The β-zone width was revealed as a significant lateralizing factor for unilateral POAG, whereas the γ-zone was not associated with the presence of glaucoma.
authors.forename: Yung Ju
authors.initials: YJ
authors.lastname: Yoo
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Lee
authors.forename: Tae-Woo
authors.initials: TW
authors.lastname: Kim
mesh_terms: D016570:Bruch Membrane / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009896:Optic Atrophy / Q000175:diagnosis* / Q000209:etiology; D009898:Optic Disk / Q000473:pathology*; D011446:Prospective Studies; D041623:Tomography, Optical Coherence / Q000379:methods*