retinal nerve fiber layer thickness and physiological central corneal thickness in healthy myopic eyes

purpose: to examine the relationship between retinal nerve fiber layer (rnfl) measurements obtained using scanning laser polarimetry with variable corneal compensation (vcc) and central corneal thickness (cct) measurements using pentacam in myopic patients methods: the study included 45 eyes from 45 myopic patients with intraocular pressure (iop) measurements≤21 mmhg. all participants had normal optic discs and normal standard automated perimetry visual fields. all patients underwent imaging with the gdx vcc and pentacam. we examined the relationship between gdx vcc rnfl measurements and cct. results: mean spherical equivalent (se) was -3.65±1.1 d (range: -1.00 to -6.5 d). mean cct was 530.9±24.32 µm with a range of 488 to 596 µm. tsnit (temporal, superior, nasal, inferior, temporal) average, inferior average, superior average, tsnit standard deviation (sd) and nerve fiber indicator (nfi) were not correlated with cct. there were no correlations between rnfl thickness and refraction, age, corneal volume and mean keratometry. however, rnfl in patients with cct≤530 µm was significantly thinner than in those with thick corneas. conclusion: rnfl measurements obtained using gdx vcc may not correlate with corneal thickness (cct) and refraction in myopic patients. myopic patients with cct≤530 have thinner rnfl than in those with thick corneas.  iranian journal of ophthalmology 200921(2):19-24 © 2009 by the iranian society of ophthalmology