title: Correlation of Retinal Nerve Fiber Layer Thickness and Axial Length on Fourier Domain Optical Coherence Tomography.
abstract: BACKGROUND
  The assessment of the peripapillary Retinal Nerve Fiber Layer (RNFL) thickness has been an important tool for evaluating and diagnosing glaucoma and its progression. Literature suggests that myopic eyes are at an increased risk for developing glaucoma. This study gives an insight into the relationship of RNFL thickness to the axial length in normal population.
  
  
  OBJECTIVE
  To correlate the RNFL thickness and the axial length in normal individuals with Fourier domain Optical Coherence Tomography (OCT).
  
  
  METHODS
  In the current study, 298 eyes of 149 normal individuals (10 years or older) with or without refractive error were recruited. The RNFL thickness was measured using Optovue (RTVue) three-dimensional Fourier domain OCT.
  
  
  RESULTS
  We observed an inverse relationship between average RNFL thickness and increasing axial length(p=0.003). Maximum RNFL thickness was seen in the Infero-Temporal (IT) quadrant and minimum in the Supero-Nasal (SN) quadrant. RNFL thickness did not show any tendency to decline with age using the Pearsons correlation (r=0.07). Females had an increased RNFL thickness in the Supero-Temporal (ST) and Infero-Nasal (IN) quadrant (p-value 0.046 and 0.02) in comparison to males. There was a statistically significant thinning in Ganglion Cell Complex (GCC) with increasing axial length (p-value 0.000).
  
  
  CONCLUSIONS
  The current study suggests that the average RNFL thickness does not decrease with age. The RNFL and GCC thickness shows an inverse correlation with axial length of the eyeball hence observations have to be carefully interpreted in myopic eyes. Clinicians need to keep the anatomical variations in RNFL for better patient management.
authors.affiliation: Vitreoretina Fellow at Sankara Nethralaya Chennai, India.
authors.forename: Abhinav
authors.initials: A
authors.lastname: Dhami
authors.affiliation: Associate Professor, Department of ophthalmology, Himalayan Institute of Medical Sciences, Dehradun, India.
authors.forename: Renu
authors.initials: R
authors.lastname: Dhasmana
authors.affiliation: Professor Emiratus, Department of Ophthalmology, Himalayan Institute of Medical Sciences, Dehradun, India.
authors.forename: R C
authors.initials: RC
authors.lastname: Nagpal
keywords: Best corrected visual acuity; Ganglion cell complex; Goldmann’s applanation tonometer