Assessment of Retinal Nerve Fiber Layer Thickness in Healthy, Full-Term Neonates

Abstract

To measure average retinal nerve fiber layer (RNFL) thicknesses in healthy, full-term neonates. Descriptive research to develop normative data. Healthy infants born between 37 and 42weeks postmenstrual age were imaged with hand-held spectral-domain optical coherence tomography. A custom script segmented the RNFL; the fovea and optic nerve center were manually selected. A second script measured the average RNFL thickness along the papillomacular bundle, defined as the arc from-15 degrees to+15 degrees on the axis from the optic nerve to fovea, with radii of 1.1, 1.3, 1.5, and 1.7mm from the center of the optic disc. Shapiro-Wilk W tests assessed these measurements for normality to determine the age-appropriate radial distance for subsequent analyses. Average RNFL thicknesses for four temporal 45-degree sectors (superior temporal, temporal superior, temporal inferior, and inferior temporal) and the temporal quadrant were calculated and compared to demographic parameters for all infants. Fifty full-term infants were adequately imaged for RNFL analysis. RNFL thicknesses at 1.5mm radial distance from the optic nerve were the most normally distributed. While there was a trend toward greater mean superior temporal RNFL thickness for both black and Hispanic vs white infants (128 ± 27μm, 124 ± 30μm, and 100 ± 19μm, respectively, P= .04 for both comparisons), there were no other significant differences noted in RNFL thicknesses by race, sex, gestational age, or birth weight. We present RNFL thickness measurements for healthy, full-term infants that may serve as normative data for future analyses.