title: Evaluation of peripapillary retinal nerve fiber layer thickness in myopic eyes by spectral-domain optical coherence tomography.
abstract: OBJECTIVE
  To investigate the influence of myopia on peripapillary retinal nerve fiber layer (RNFL) thickness using Cirrus optical coherence tomography (OCT) in normal eyes.
  
  
  METHODS
  Ninety-eight eyes of normal participants with various degrees of myopia were recruited in this study. The RNFL thickness was measured with high-definition (HD), spectral-domain Cirrus OCT (Cirrus HD-OCT; Carl Zeiss, Dublin, CA). The association between RNFL thickness and its spherical equivalent was evaluated with linear regression analysis.
  
  
  RESULTS
  The RNFL thickness was 119.2±16.8 μm, 117.1±16.8 μm, 75.9±16.1 μm, and 64.9±9.8 μm in the superior, inferior, temporal, and nasal quadrants, respectively, with an average thickness of 94.3±8.6 μm. The mean RNFL thickness was thinner in highly and moderately myopic eyes (93±7.9 μm and 92.6±7.7 μm, respectively, P=0.0001) compared with low myopic eyes (102.2±9 μm). A significant linear correlation was found between the spherical equivalent and the RNFL thickness in the superior (r=0.386, P=0.0001) and inferior quadrants (r=0.448, P=0.0001), and the average RNFL thickness (r=0.373, P=0.0001).
  
  
  CONCLUSIONS
  Myopia can be a confounding factor in the assessment of RNFL thickness attributed to its influence on the RNFL thickness. Therefore, we recommend a careful interpretation of RNFL data, especially those obtained from eyes with moderate-to-high myopia.
authors.affiliation: Department of Ophthalmology, International Islamic University Malaysia, Kuantan, Malaysia. paymankurd@yahoo.com
authors.forename: Payman A-K
authors.initials: PA
authors.lastname: Mohammad Salih
mesh_terms: D000328:Adult; D001369:Axons / Q000473:pathology*; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005901:Glaucoma / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000145:classification / Q000175:diagnosis*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012307:Risk Factors; D041623:Tomography, Optical Coherence; D055815:Young Adult