Purpose
To measure average retinal nerve fiber layer (RNFL) thicknesses in healthy, full term neonates.
Methods
Healthy infants born between 37-42 weeks post-menstrual age were imaged with handheld spectral domain optical coherence tomography (Bioptigen, Inc., Research Triangle Park, NC). A custom MATLAB script (Mathworks, Inc., Natick, MA) 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° to +15° on the axis from the optic nerve to fovea, with radii of 1.1, 1.3, 1.5, and 1.7 mm 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° sectors (superior temporal, temporal superior, temporal inferior, and inferior temporal) as well as the temporal quadrant were calculated and compared to demographic parameters for all infants.
Results
Fifty full-term infants were adequately imaged for RNFL analysis. RNFL thicknesses at 1.5 mm radial distance from the optic nerve were the most normally distributed. While there was a trend towards greater mean superior temporal RNFL thickness for both Black and Hispanic versus White infants (128 ±27, 124 ±30, and 100 ±19 μm, respectively, P=0.04 for both comparisons), there were no other significant differences noted in RNFL thicknesses by race, sex, gestational age, or birth weight.
Conclusions
We present RNFL thickness measurements for healthy, full term infants that may serve as normative data for future analyses.