title: Asymmetry analysis of macular inner retinal layers for glaucoma diagnosis.
abstract: OBJECTIVE
  To determine if asymmetry in thickness of the retinal nerve fiber layer (RNFL), ganglion cell layer, ganglion cell complex, and total retina between upper and lower macula halves can predict glaucoma.
  
  
  METHODS
  Retrospective case-control series.
  
  
  METHODS
  One hundred twenty-two eyes of 122 patients (30 normal eyes and 30 preperimetric, 31 early, and 31 advanced glaucoma eyes) were studied. The RNFL, ganglion cell layer, ganglion cell complex, and total retina were segmented and measured on 10 vertical B-scans over a 30 × 15 degree macular area. The equation asymmetry index =|log10 (lower hemiretinal thickness/upper hemiretinal thickness)| was used to calculate asymmetry indices for 8 pairs of upper and lower 0.5-mm segments equidistant from the fovea on each scan. Areas under the receiver operating characteristic curve (AROCs) for mean thickness and mean asymmetry index of 10 B-scans were compared.
  
  
  RESULTS
  The overlap in values for normal and glaucomatous eyes was minimal for the ganglion cell layer asymmetry index. Thickness parameters decreased with the severity of glaucoma, whereas asymmetry indices did not. AROCs for thickness measurements tended to increase with increasing glaucoma severity (preperimetric, 0.746-0.808; early, 0.842-0.940; advanced, 0.943-0.995), whereas AROCs for asymmetry indices did not have distinct ranges according to glaucoma severity (advanced, 0.819-0.996; early, 0.861-0.998; preperimetric, 0.773-0.994). The AROC for the ganglion cell layer asymmetry index remained almost perfect regardless of glaucoma severity (0.994-0.998).
  
  
  CONCLUSIONS
  Macular retinal layer thickness asymmetry indices, particularly for the ganglion cell layer, show promise as early indicators of glaucomatous retinal damage.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan; Department of Ophthalmology, Saitama Medical University, Saitama, Japan. Electronic address: hangai@saitama-med.ac.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Hangai
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Nakano
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Takayama
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Yugo
authors.initials: Y
authors.lastname: Kimura
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Miyake
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Tadamichi
authors.initials: T
authors.lastname: Akagi
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Hanako Ohashi
authors.initials: HO
authors.lastname: Ikeda
authors.affiliation: The Institute of Statistical Mathematics, Tokyo, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Noma
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000368:Aged; D019540:Area Under Curve; D016022:Case-Control Studies; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D012372:ROC Curve; D012160:Retina / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence