Myopia affects retinal nerve fiber layer measurements as determined by optical coherence tomography

J Glaucoma. 2009 Sep;18(7):501-5. doi: 10.1097/IJG.0b013e318193c2be.

Abstract

Purpose: To determine whether increasing myopia is associated with thinner peripapillary retinal nerve fiber layer (RNFL) when measured by Stratus optical coherence tomography (OCT).

Design: Observational cross-sectional study.

Methods: Normal subjects with myopia underwent refractometry, axial length measurement (IOL Master), optic nerve examination, and OCT (12 fast RNFL scans/eye). The more myopic eye was chosen as the study eye. Correlation coefficients were calculated for demographic and optic disk characteristics, and degree of myopia.

Results: Mean age (n=27) was 34+/-8 years (range: 23 to 54). Mean cup-to-disk ratio was 0.38 with 41% large and 59% medium disk size. Eight subjects had peripapillary atrophy and 6 had disk tilt. Mean spherical equivalent was -5.40 D (range: -1.25 to -11.25), with mean axial length of 25.65 mm (range: 22.63 to 27.92). No significant associations were found between RNFL thickness and age (P=0.20), sex, disk size, cup-to-disk ratio, tilt, or peripapillary atrophy. RNFL thickness decreased with higher axial length (overall R=-0.70, P<0.001, superior R=-0.60, P=0.001, and inferior R=-0.60, P=0.001), and higher spherical equivalent (overall R=-0.52, P=0.005, superior R=-0.41, P=0.03, and inferior R=-0.45, P=0.02). Overall RNFL thickness decreased 7 mum/1 mm of axial length, and 3 mum/1 D sphere.

Conclusions: Moderately myopic subjects tend to have thin peripapillary RNFL, mainly at the superior and inferior poles, as measured by Stratus OCT. This phenomenon should be considered when interpreting a glaucoma suspect's Stratus OCT measurements compared with the normative database.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cross-Sectional Studies
  • Female
  • Glaucoma / physiopathology
  • Humans
  • Intraocular Pressure
  • Male
  • Middle Aged
  • Myopia / physiopathology*
  • Nerve Fibers / physiology*
  • Refraction, Ocular / physiology
  • Retinal Ganglion Cells / physiology*
  • Tomography, Optical Coherence