Retinal Nerve Fibre Layer Measurements in Normal Eyes in Zaria Using Optical Coherence Tomography

Abstract

Purpose: To determine the retinal nerve fiber layer (RNFL) measurements in normal eyes in Zaria and to investigate the effect of age and axial length on RNFL thickness. Materials and Methods Forty eyes of 40 healthy subjects aged between 18 and 73 underwent peripapillary RNFL thickness measurement by a series of three circular scans with a 3.4 mm diameter (Stratus optical coherence tomography, RNFL thickness 3.4 acquisition protocol). The mean RNFL values were correlated with age and axial length. The statistical analysis used was Pearson's coefficient of correlation, linear regression, and paired t-test with the analyse-it® software for Excel. Results: The mean age of the subjects was 35 years, range18.0-73.0 years. Mean RNFL thickness global average was 107.055 μm standard deviation (SD 9.219 μm) with the RNFL in the superior quadrant being the thickest (mean: 139.0 mm SD 15.0 mm), there was no significant correlation with axial length in this study (P = 0.56) but there was a negative correlation between global RNFL average and age (r = ­0.56 P = 0.0002). Conclusion: This study provides normative RNFL values for normal eyes in Zaria locality. It can be used as a reference for the normal measurements of RNFL in this environment. Age demonstrates a significant negative correlation with RNFL thickness.