Myelinated Retinal Nerve Fibers in Children: OCT Imaging, Refractive Error and Vision

Scott O Brien,Derek T Sprunger,Maria E Lim,Jingyun Wang

doi:10.4172/2155-9570.1000610

Abstract

Purpose: To characterize peripapillary retinal nerve fiber layers (RNFL’s) and macular retinal structure in children with unilateral myelinated retinal nerve fibers (MRNFs). We also investigated the correlation between MRNF abnormalities and refractive error/visual acuity. Methods: Twelve children (7-13 years old) with MRNFs were included. Fourier domain optical coherence tomography was used to image both the peripapillary RNFL and the macular retinal structures in 6 patients. Using the instrument’s segmentation software, global RNFL thickness and central subfield thickness (CST) of the macula were analyzed. Planimetry was used to quantify the MRNF area observed on fundus photography. Visual acuity and cycloplegic refractive errors (spherical equivalent) were also recorded. Results from the MRNF-affected eye were compared with the fellow eye. Results: The global RNFL thickness of the eyes with MRNFs (152 ± 13.9 μm) was significantly higher than the fellow eyes (114.3 ± 15.2 μm) (P=0.003). The global RNFL thickness of the fellow eye was in normal range, and no significant differences were detected in macular CST between the eyes with MRNFs and fellow eyes (P=0.403). The MRNF area was significantly correlated with the spherical equivalent of the affected eye (P=0.002). In addition, the interocular difference of RNFL thickness between eyes was significantly correlated with anisometropia (P=0.03). Conclusions: Eyes with MRNFs show a significantly thicker global peripapillary RNFL trend as compared to the fellow eye, and the area of MRNFs is correlated with the development of myopia and anisometropia, but not correlated to visual acuity.

Highlights

Myelinated retinal nerve fibers (MRNFs) are developmental anomalies of the retina that appear as white to grey-white striated patches with feathery edges, often distributed around or contiguous with the optic disc and surrounding the vascular arcades
Schmidt et al reported that widespread MRNFs of the optic disc are associated with the development of myopia in adult patients, but they did not quantify the correlation between MRNF surface area and refractive error [4]
Macular thickness was within the normal range, we found that the peripapillary retinal nerve fiber layer (RNFL) of the MRNF eye was significantly thicker than the fellow eye

Summary

Introduction

Myelinated retinal nerve fibers (MRNFs) are developmental anomalies of the retina that appear as white to grey-white striated patches with feathery edges, often distributed around or contiguous with the optic disc and surrounding the vascular arcades. Based on a fundus photography study including 5789 patients, Kodama et al reported that MRNFs occur in approximately 0.57% of the population, most often involving superior and inferior-temporal peripapillary areas. Patients with MRNFs may be asymptomatic or show significant visual dysfunction with acuity ranging from 20/40 to hand motion in previous reports [2,3]. Myopic anisometropia and amblyopia are often suggested to be associated with unilateral MRNFs, but their relationships with MRNF surface areas were not quantified [3]. Schmidt et al reported that widespread MRNFs of the optic disc are associated with the development of myopia in adult patients, but they did not quantify the correlation between MRNF surface area and refractive error [4]. Most previous studies investigating this developmental eye disease--MRNF and refractive error development—focus exclusively on adult patients. Kee et al reported that the area of MRNFs is related to visual acuity improvement in 12 children; there is no quantitative MRNF data to demonstrate this relationship [2]

Methods

Results

Conclusion