title: Asymmetry Analysis of Macular Inner Retinal Layers for Glaucoma Diagnosis: Swept-Source Optical Coherence Tomography Study.
abstract: OBJECTIVE
  To report an asymmetry analysis of macular inner retinal layers using swept-source optical coherence tomography (OCT) and to evaluate the utility for glaucoma diagnosis.
  
  
  METHODS
  Observational, cross-sectional study.
  
  
  METHODS
  Seventy normal healthy subjects and 62 glaucoma patients.
  
  
  METHODS
  Three-dimensional scans were acquired from 70 normal subjects and 62 open angle glaucoma patients by swept-source OCT. The thickness of the retinal nerve fiber layer, ganglion cell-inner plexiform layer (GCIPL), ganglion cell complex, and total retina were calculated within a 6.2×6.2 mm macular area divided into a 31×31 grid of 200×200 μm superpixels. For each of the corresponding superpixels, the thickness differences between the subject eyes and contra-lateral eyes and between the upper and lower macula halves of the subject eyes were determined. The negative differences were displayed on a gray-scale asymmetry map. Black superpixels were defined as thickness decreases over the cut-off values.
  
  
  RESULTS
  The negative inter-ocular and inter-hemisphere differences in GCIPL thickness (mean ± standard deviation) were -2.78 ± 0.97 μm and -3.43 ± 0.71 μm in the normal group and -4.26 ± 2.23 μm and -4.88 ± 1.46 μm in the glaucoma group. The overall extent of the four layers' thickness decrease was larger in the glaucoma group than in the normal group (all Ps<0.05). The numbers of black superpixels on all of the asymmetry maps were larger in the glaucoma group than in the normal group (all Ps<0.05). The area under receiver operating characteristic curves of average negative thickness differences in macular inner layers for glaucoma diagnosis ranged from 0.748 to 0.894.
  
  
  CONCLUSIONS
  The asymmetry analysis of macular inner retinal layers showed significant differences between the normal and glaucoma groups. The diagnostic performance of the asymmetry analysis was comparable to that of previous methods. These findings suggest that the asymmetry analysis can be a potential ancillary diagnostic tool.
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea.|Department of Ophthalmology, Jeju National University Hospital, Jeju-si, South Korea.
authors.forename: Sang-Yoon
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea.|Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Eun Kyoung
authors.initials: EK
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea.|Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Ki Ho
authors.initials: KH
authors.lastname: Park
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea.|Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Dong Myung
authors.initials: DM
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea.|Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Jin Wook
authors.identifier: http://orcid.org/0000-0001-7311-7080
authors.initials: JW
authors.lastname: Jeoung
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008266:Macula Lutea / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012165:Retinal Ganglion Cells / Q000502:physiology; D041623:Tomography, Optical Coherence