Retinal nerve fibre layer thickness profile in normal eyes using third-generation optical coherence tomography

Abstract

Aims: To establish four normal retinal nerve fibre layer (RNFL) thickness radial profiles based on third-generation optical coherence tomography (OCT) and to compare them with previously reported histologic measurements. Methods: A total of 20 normal eyes were studied. A circular scan was adjusted to the size of the optic disc and three scans were performed with this radius and every 200 m thereafter, up to a distance of 1400 μm. Four different radial sections (superotemporal, superonasal, inferonasal, and inferotemporal) were studied to establish RNFL thickness OCT profiles. Additionally, two radial scans orientated at 45 and 135° crossing the optic disc centre were performed in six of 20 eyes, and RNFL thickness was measured at disc margin. Results: Quadrant location and distance from disc margin interaction in RNFL thickness was statistically significant (P < 0.001). The RNFL thickness decreased (P < 0.001) as the distance from the disc margin increased for all sections. The measurements automatically generated by the OCT built-in software were thinner (P < 0.001) than histologic ones close to the disc margin. Conclusions: Four normal OCT RNFL profiles were established and compared with histological data obtained from the same area. RNFL measurements assessed by OCT 3 were significantly thinner close to the optic disc margin. © 2006 Nature Publishing Group All rights reserved.