Evaluation of retinal nerve fibre layer thickness by optical coherence tomography in emmetropic and myopic patients

Abstract

In myopic eyes, the elongation of the globe leads to mechanical stretching and thinning of the retina. Therefore, it is conceivable that the extent of the elongation would be related to the degree of retinal thinning, although it is yet to be ascertained whether the retinal nerve fibre layer (RNFL) thickness is decreased at the histologic level. To evaluate RNFL by OCT in Emmetropic and Myopic patients and evaluate the relationship between RNFL thickness and the grade of myopia and Axial Length. The present study was carried out at the department of ophthalmology, Teerthanker Mahaveer Medical College & Research Centre, Moradabad. Peripapillary RNFL thickness of all subjects were tabulated for group 1 (emmetropics) and Group 2 comparing them to grades of myopia, axial length, age, refractive status and cup disc ratio. The mean right and left side axial length was significantly more among myopic subjects compared to emmetropic subjects. The mean RNFL superior, Inferior, Temporal and Nasal was significantly more among emmetropic compared to low myopia which was significantly more than moderate myopia which was significantly more than high myopia thereby showing a decrease in the RNFL thickness with grades of myopia. We observed that with increasing grades of myopia the RNFL thickness decreased. On comparing emmetropes and myopes on the basis of axial length, we observed that with increasing axial length in various degrees of myopia, the average RNFL thickness also decreased in various quadrants.