Retinal nerve fiber layer thickness in a healthy Turkish population measured by optical coherence tomography

Abstract

BACKGROUND: Normative optical coherence tomography (OCT) data is required for different subsets of the population as ethnic differences in retinal nerve fiber layer (RNFL) thickness have been reported. An OCT database for the normal Turkish population is not commercially available. OBJECTIVES: Quantify peripapillary RNFL thickness in a Turkish population. DESIGN: Cross-sectional, descriptive study. SETTING: Numune Training and Research Hospital, Adana, Turkey. SUBJECTS AND METHODS: RNFL measurements performed by Spectral OCT with a circular scan with 3.4 mm circle were centered around the optic disc of the right eye of each subject. Correlation of the effects of age and gender on RNFL thickness was analyzed. MAIN OUTCOME MEASURE(S): Correlation and measurements of RNFL. Retinal nerve fiber layer thickness measurements were obtained for the entire circumference of the optic nerve head. RESULTS: In 307 healthy subjects consisting of 135 (44%) males and 172 (56%) females, with a mean (SD) age of 35.1 (9.6) years (range, 20–50 years), RNFL was superior: 132.2 (16.63) μm, inferior: 139.1 (14.53) μm, nasal: 96.2 (14.23) μm, temporal: 79.8 (10.7) μm. The mean (SD) RNFL thickness for the group was 111.5 (9.3) μm. There was no significant difference between the average RNFL thicknesses of age groups nor between males and females (P=.1, P=.42), and no significant correlation with respect to age (P=.430, r=ࢤ.04). There was a statistically significant difference between the inferior quadrants of the two genders (P=.04). CONCLUSIONS: RNFL thickness did not vary significantly with gender. A weak negative but statistically nonsignificant correlation between average RNFL thickness and age was found. LIMITATIONS: The participants were young adults or at early middle age so age effects on RNFL thickness may not be explained. The data does not reflect the entire Turkish population, which is not homogeneous.