Assessing the relationship between central corneal thickness and retinal nerve fiber layer thickness in healthy subjects.

Abstract

To determine the relationship between central corneal thickness (CCT) and retinal nerve fiber layer (RNFL) thickness obtained by scanning laser polarimetry (GDx-VCC; Carl Zeiss Meditec, Dublin, California, USA), confocal scanning laser ophthalmoscopy (HRT II; Heidelberg Engineering, Heidelberg, Germany), and optical coherence tomography (Stratus OCT; Carl Zeiss Meditec). Multicenter clinical trial, retrospective cross-sectional study. One hundred and nine healthy subjects from the Advanced Imaging in Glaucoma Study were enrolled in this study. All subjects had a standard clinical examination, including visual field (VF) and good-quality scans from all three imaging devices. CCT was measured using an ultrasonic pachymeter. A linear mixed-effects model was used to assess the relationship between RNFL thickness and CCT, accounting for clustering of eyes within subjects, testing site, ethnicity, family history of glaucoma, axial length intraocular pressure, and VF global indices. For OCT and GDx, there was a slight nonstatistically significant positive relationship between CCT and RNFL thickness. For HRT, there was a slight nonstatistically significant negative relationship between CCT and RNFL thickness. Relationships for each device were found to differ between sites. CCT was not statistically significantly related to RNFL thickness in healthy eyes.