title: Retinal Nerve Fiber Layer Thicknesses in Three Different Optic Nerve Head Size Groups Measured by Cirrus Spectral Domain Optical Coherence Tomography.
abstract: OBJECTIVE
  To compare the retinal nerve fiber layer (RNFL) thicknesses in three different optic nerve head (ONH) size groups measured by Cirrus spectral domain optical coherence tomography (OCT).
  
  
  METHODS
  Between January and March 2013, 253 eyes of 253 healthy subjects were enrolled in this study (mean age: 42.7±7.4 years [28-62 years]; 121 men and 132 women). The patients were divided into 3 groups according to ONH size: 77 patients in the "small ONH" group (ONH area <1.63 mm2), 90 patients in the "medium ONH" group (ONH area 1.63-1.97 mm2), and 86 patients in the "large ONH" group (ONH area >1.97 mm2).
  
  
  RESULTS
  There were significant differences in superior (p=0.008), inferior (p=0.004) and average RNFL thickness (p=0.001) between the small, medium and large ONH groups. Positive correlations between ONH size and inferior/average RNFL thicknesses were significant but very weak (r=0.150, p=0.017 and r=0.157, p=0.013 respectively).
  
  
  CONCLUSIONS
  RNFL thickness as measured by Cirrus OCT is positively correlated with ONH size and the differences in RNFL thickness were statistically significant between groups. This correlation and difference may be the result of a varying distance between the circular scan and the ONH margin.
authors: Başkent University Faculty of Medicine, Department of Ophthalmology, Ankara, Turkey.
authors: Sirel
authors: S
authors: Gür Güngör
authors: Başkent University Faculty of Medicine, Department of Ophthalmology, Ankara, Turkey.
authors: Ahmet
authors: A
authors: Akman
authors: Başkent University Faculty of Medicine, Department of Ophthalmology, Ankara, Turkey.
authors: Ali
authors: A
authors: Küçüködük
authors: Başkent University Faculty of Health Sciences, Ankara, Turkey.
authors: Meriç
authors: M
authors: Çolak
keywords: Retinal nerve fiber layer; optic nerve head; optical coherence tomography