title: Topographic characteristics of the optic nerve head measured with scanning laser tomography in normal Japanese subjects.
abstract: OBJECTIVE
  Few studies have been performed regarding the topographic information obtained with the Heidelberg retina tomograph (HRT) in normal Japanese. In this study, we examined the factors influencing optic disc parameters and hemisphere symmetry obtained with the HRT in normal Japanese subjects.
  
  
  METHODS
  Mean values and the standard deviation range for the main HRT parameters were evaluated in 223 eyes of 223 normal Japanese subjects. The influence of age, sex, and disc size on HRT topographic data was analyzed. The superior and inferior hemisphere topographic parameters were compared.
  
  
  RESULTS
  Disc area showed a significant difference by sex (P = 0.0493). Rim volume (r = -0.208, P = 0.019), height variation contour (r = -0.275, P = 0.001), and mean retinal nerve fiber layer (RNFL) thickness (r = -0.366, P = 0.001) declined with age. All parameters except height variation contour and mean RNFL thickness showed a clinically significant correlation with disc size (-0.159 < r < 0.719, P < 0.01). Cup parameters in the superior hemisphere were significantly greater than those in the inferior hemisphere. In contrast, rim parameters in the superior hemisphere were significantly smaller than those in the inferior hemisphere.
  
  
  CONCLUSIONS
  Some factors, namely, sex, age, and disc size, affected the optic disc parameters in the HRT measurements. Possible parameter asymmetry between the two hemispheres should be considered in normal eyes.
authors.affiliation: Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan. gifhu@aol.com.|Uchida Eye Clinic, Gifu, Japan. gifhu@aol.com.
authors.forename: Hideya
authors.initials: H
authors.lastname: Uchida
authors.affiliation: Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Ophthalmology, Tokyo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Araie
authors.affiliation: Department of Ophthalmology, Tokyo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Goji
authors.initials: G
authors.lastname: Tomita
authors.affiliation: Division of Ophthalmology and Visual Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Shirakashi
authors.affiliation: Yoshikawa Eye Clinic, Tokyo, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Yoshikawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000166:cytology*; D012016:Reference Values; D015203:Reproducibility of Results; D012737:Sex Factors; D041623:Tomography, Optical Coherence / Q000379:methods*