Effect of error of refraction and axial length on peripapillary retinal nerve fiber layer thickness in normal people and glaucomatous patients using optical coherence tomography

Abstract

Background: The measurement of retinal nerve fibre layer (RNFL) thickness is widely recognized as a very delicate tool of optic nerve damage, since it manifests before the manifestation of visual field impairment. Aim of the work: The aim of this study was to evaluate the effect of refractive status and axial length of the eye on the thickness of the peripapillary RNFL in individuals with and without glaucoma. This was achieved via the use of optical coherence tomography.Methods: This research was carried on 54 eyes of 27 glaucomatous patients and 54 eyes of 27 healthy. Inclusion criteria were participants aged 20-60 years old, with clear ocular media and Glaucomatous patients were previously diagnosed by fundus examination, IOP measurement and visual field. Results: The thickness of the RNFL in different quadrants is influenced by factors such as axial length, refractive error, and age. However, it has been discovered that changes in axial length or age do not have an impact on the thickness of the RNFL in the temporal quadrant, unlike the other quadrants. Multivariate analysis show that axial length and age are the main factors affecting RNFL thickness in myopic eyes either normal or glaucomatous. Conclusions: The diagnosis of glaucoma with myopia is a controversy due to the alterations in the optic disc. This research used an OCT technology to evaluate the effect of axial length and refractive error on RNFL thickness. The findings revealed that changes in axial length had a differential effect, with the exception of the temporal quadrant. The presence or severity of changes in the temporal quadrant is often minimal or nonexistent. The thinning in the temporal quadrant may indicate the glaucoma.