title: Peripapillary retinal nerve fiber layer and optic nerve head characteristics in eyes with situs inversus of the optic disc.
abstract: OBJECTIVE
  This study was performed to investigate the peripapillary retinal nerve fiber layer (RNFL) and optic nerve head (ONH) characteristics, as determined using a spectral-domain optical coherence tomography (OCT), in eyes with situs inversus of the optic disc.
  
  
  METHODS
  The peripapillary RNFL and the ONH were assessed in 12 eyes belonging to 6 subjects with situs inversus of the optic disc (situs inversus group) and 24 eyes in 12 age-matched, sex-matched, and refractive error-matched healthy subjects (control group) by using OCT. The average, quadrant, and clock-hour RNFL thicknesses (clock-hour 9 on the scan represented the temporal side of the optic disc in both eyes), the superior/inferior RNFL peak locations, and ONH characteristics such as disc area, rim area, cup-to-disc ratio, vertical cup-to-disc ratio, and cup volume were obtained. The differences in RNFL and ONH characteristics between the 2 groups were analyzed.
  
  
  RESULTS
  The situs inversus group had a thicker RNFL in the clock-hour sectors 3 and 4, a thinner RNFL in the clock-hour sectors 7, 8, and 11, and more nasally located superior and inferior RNFL peak locations than the control group (P≤0.001). The situs inversus group had a smaller cup-to-disc area ratio, smaller vertical cup-to-disc ratio, and a lesser cup volume than the control group (P<0.01).
  
  
  CONCLUSIONS
  Eyes with situs inversus of the optic disc showed different peripapillary RNFL and ONH characteristics from those without this abnormality. These findings should be considered when assessing eyes with situs inversus of the optic disc.
authors.affiliation: *Department of Ophthalmology, Myung-Gok Eye Research Institute, Konyang University, Kim's Eye Hospital, Seoul †Department of Ophthalmology, Konyang University College of Medicine, Daejeon ‡Anyang Seoul Eye Clinic, Anyang, Korea.
authors.forename: Sunah
authors.initials: S
authors.lastname: Kang
authors.forename: Sunyoung
authors.initials: S
authors.lastname: Jin
authors.forename: Kyu Hwa
authors.initials: KH
authors.lastname: Roh
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000368:Aged; D005124:Eye Abnormalities / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000002:abnormalities* / Q000473:pathology*; D012030:Refractive Errors / Q000209:etiology; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods