title: Microstructure of parapapillary atrophy: beta zone and gamma zone.
abstract: OBJECTIVE
  To examine the morphologic features of parapapillary atrophy by using enhanced depth imaging optical coherence tomography (EDI-OCT) and color fundus photographs.
  
  
  METHODS
  The clinical observational comparative study included 80 normal eyes of 46 subjects and 80 eyes of 46 patients with primary open-angle glaucoma. Both groups did not vary significantly in axial length (P = 0.62) and refractive error (P = 0.30). Color fundus photographs and cross-sectional B-scan images obtained by EDI-OCT were examined. On the EDI-OCT images, we measured a gamma zone defined as the region between the temporal disc margin to the beginning of Bruch's membrane, and a beta zone defined as Bruch's membrane without retinal pigment epithelium.
  
  
  RESULTS
  The gamma zone (mean area: 1.13 ± 2.04 mm(2)) was significantly associated with longer axial length (P < 0.001; standardized coefficient beta: 0.48), longer vertical disc diameter (P < 0.001; beta: 0.43), older age (P = 0.008; beta: 0.22), and the absence of glaucoma (P = 0.03; beta: -0.19). The beta zone (mean area: 0.85 ± 0.60 mm(2)) was associated with longer axial length (P < 0.001; beta: 0.39) and the presence of glaucoma (P < 0.001; beta: 0.48).
  
  
  CONCLUSIONS
  In addition to associations with older age, increasing myopia, and larger disc size, the EDI-OCT-defined gamma zone of parapapillary atrophy was associated with the absence of glaucoma, whereas the EDI-OCT-defined beta zone was associated with the presence of glaucoma. Differentiation between the beta zone and the gamma zone may be clinically useful.
authors: Department of Ophthalmology and Vision Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors: Yi
authors: Y
authors: Dai
authors: Jost B
authors: JB
authors: Jonas
authors: Haili
authors: H
authors: Huang
authors: Min
authors: M
authors: Wang
authors: Xinghuai
authors: X
authors: Sun
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016570:Bruch Membrane / Q000473:pathology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000150:complications / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008875:Middle Aged; D009896:Optic Atrophy / Q000209:etiology / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D010857:Pigment Epithelium of Eye / Q000473:pathology*; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult