Macular Retinal Ganglion Cell Layer Measurement Obtained With HR-OCT in Healthy Subjects and Correlation With Age and Refractive Status

Abstract

Purpose: : Fast scanning high resolution optical coherence tomography (HR-OCT) enables quantitative analysis of histological retinal layers. Aim of the study was to correlate the thickness of macular retinal ganglion cell layers (RGCL) measured by HR-OCT with age and refractive status in healthy subjets.

Methods: : Macular HR-OCT scans (Cirrus, Carl Zeiss Meditec) were obtained in 48 healthy subjects (age 20 to 78 years; refraction between -5.5 sph and +6.0 sph) using raster scanning of a 20x20 field at a resolution of 512x128x1024 voxels. The scans were analysed using a software algorithm for automated segmentation and quantification in retinal layers. We analysed retinal nerve fibre layer (RNFL), RGCL, RGCL together with the inner plexiform layer (RGIPL), photoreceptor layer (PRL) and the retinal thickness (RT). Statistical analysis was performed using linear regression analysis.

Results: : The thickness of the RNFL did not correlate with age or refractive status. There was a correlation between RGCL thickness and refraction (correlation cofficient (CC) 0.287, p= 0.034), but not with age (CC -0.085, n.s.). RGIPL thickness was also correlated with refraction (CC 0.308, p= 0.017) but not with age (CC -0.136, n.s.). There was no correlation of RT with age and refractive status.

Conclusions: : We were able to show a correlation between the RGCL and RGIPL as assessed with rapid frequency-domain HR-OCT with refractive status. These findings in a yet limited data set indicate that diagnostic tools aiming at use of macular RGCL or RGIPL for glaucoma diagnosis will have to take into account the patients refractive error.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • refraction • retina