title: Effect of Axial Length on Macular Ganglion Cell Complex Thickness and on Early Glaucoma Diagnosis by Spectral-Domain Optical Coherence Tomography.
abstract: To investigate the effects of the axial length (AL)-related ocular magnification on the thickness of the macular ganglion cell complex (mGCC), and the diagnostic accuracy of the built-in normative database of the spectral-domain optical coherence tomographic (SD-OCT) instrument for early glaucoma detection.
  
  
  
  This retrospective study included 41 eyes with early primary open-angle glaucoma and 36 normal eyes. The mGCC thickness within a 20-degree circle, equivalent to a 6 mm diameter in the Gullstrand model eye, was measured in the SD-OCT images. The magnification effect was corrected using Bennett formula, and the mGCC thickness within the actual 6 mm diameter circle was determined.
  
  
  
  In normal eyes, the inferior corrected mGCC was significantly correlated with the AL (β=-0.40, P=0.028), but correction for the magnification reduced the correlation. In 38 nonhighly myopic eyes, the sensitivity and specificity of the SD-OCT's significance maps for distinguishing early glaucoma were 95.0% and 94.4% when using either the uncorrected or the corrected mGCC. In 39 highly myopic eyes, the diagnostic accuracy was lower when using the uncorrected mGCC thickness (sensitivity was 95.2% and specificity was 44.4%), and was not improved when using the corrected mGCC (81.0% and 61.1%, respectively).
  
  
  
  The inferior mGCC was thinner in eyes with longer AL. The accuracy of the diagnosis with the SD-OCT built-in normative database for early glaucoma was not improved significantly by the correction of the AL-associated magnification in highly myopic eyes. Evaluation of highly myopic eyes with the nonhighly myopic normative database can lead to misdiagnosis.
authors.affiliation: *Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto †Department of Ophthalmology, Saitama Medical University, Moroyama, Saitama, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Tadamichi
authors.initials: T
authors.lastname: Akagi
authors.forename: Masanori
authors.initials: M
authors.lastname: Hangai
authors.forename: Yugo
authors.initials: Y
authors.lastname: Kimura
authors.forename: Kenji
authors.initials: K
authors.lastname: Suda
authors.forename: Tomoko
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamada
authors.forename: Munemitsu
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morooka
authors.forename: Hanako Ohashi
authors.initials: HO
authors.lastname: Ikeda
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000328:Adult; D058452:Axial Length, Eye / Q000473:pathology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D042241:Early Diagnosis; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods