Retinal nerve fiber layer thickness measurements of normal Northern Nigerian adults using optical coherence tomography

OBJECTIVE: To assess retinal nerve fiber layer (RNFL) thickness measurements of normal Northern Nigerian adults using optical coherence tomography (OCT). SUBJECTS AND METHODS: The OCT procedure was carried out with the Carl Zeiss Stratus OCT Model 3000 software version 4.0 (Carl Zeiss Meditec AG, Jena, Germany). The fast RNFL scan protocol was used to obtain RNFL thickness measurements. Student's t-test was used to compare mean RNFL thickness values. P ≤ 0.05 was considered as statistically significant. Average RNFL thickness was correlated with age. RESULTS: Two hundred and twenty eyes of 110 subjects aged 18-51 years were examined. The average RNFL thickness was 104.17 ± 10.71 μm. The mean values for the RNFL thickness were 129.15 ± 16.87 μm, 135.34 ± 20.40 μm, 85.10 ± 23.60 μm, and 67.19 ± 13.27 μm for the inferior, superior, nasal, and temporal quadrants, respectively. A statistically significant difference was found between males and females for the mean RNFL thickness (t = 3.30, P = 0.001) and for the mean superior and inferior RNFL thickness. There was a statistically significant difference between right and left eyes (t = 3.73, P = 0.001) for the mean RNFL thickness. A negative correlation was found between RNFL thickness and age (r = -0.313, P = 0.002). CONCLUSION: Normal RNFL thickness measurements in healthy Nigerian adults are presented. The RNFL was found to be thicker in females and in right eyes. The values were comparable to those of the Indian population but higher than some Caucasian values.