Retinal Nerve Fiber Layer Thickness in Normal Children Measured with Optical Coherence Tomography

Purpose: To measure the peripapillary retinal nerve fiber layer (RNFL) thickness in normal children. Design: Observational cross-sectional study. Participants: Ninety-two eyes of 92 normal children ages 4 to 17 years presenting to the Ophthalmology Clinic at the Harkness Eye Institute, Department of Ophthalmology, Columbia University. Methods: Retinal nerve fiber layer thickness was measured with optical coherence tomography (OCT). Patient cooperation and signal strength of the OCT scans were assessed. Optic disc photographs were evaluated by a glaucoma specialist in a masked fashion. Eyes with abnormal optic discs were excluded. One eye of each subject was randomly selected for statistical analysis. The effect of several factors on RNFL thickness was investigated statistically. Main Outcome Measures: Retinal nerve fiber layer thickness. Results: Ninety-one percent of the study subjects were Hispanic; 8%, African American; and 1%, Caucasian. Optical coherence tomography measurements were obtained in 117 of 121 (96.7%) subjects, and disc photographs were available for 92 of them. Mean age (±standard deviation [SD]) was 9.7±2.7 years. Mean global RNFL thickness (±SD) was 107.0±11.1 μm (range, 78.1-134.6). The RNFL was thickest inferiorly (136.9±16.9 μm) and superiorly (135.4±19.3 μm), thinner nasally (83.0±18.0 μm), and thinnest temporally (72.5±13.4 μm). In univariate regression analysis, age (P = 0.013) and refraction (P<0.001) had a significant effect on RNFL thickness; age had a significant effect on refraction (P<0.001). When controlling for refraction, age no longer had a significant effect. Conclusions: Optical coherence tomography can be used to measure RNFL thickness in children. Refraction had an effect on RNFL thickness. In normal children, variation in RNFL thickness is large. The normative data provided by this study may assist in identifying changes in RNFL thickness in children.