Myelinated nerve fiber-associated local scleral excavation and induced axial myopia

To investigate the association between the distributions of local scleral excavation and myelinated nerve fibers (MNF) and to elucidate the pathogenic mechanism of axial myopia in eyes with MNF.

In six eyes of six pediatric patients with MNF, the distribution of the MNF on fundus photography was compared with the regional excavation of the sclera on linear scans across the fovea and a peripapillary circular scan of spectral domain optical coherence tomography.

The tilting of Bruch membrane on vertical scan of spectral domain optical coherence tomography was associated with the major distribution of MNF (κ = 1, Cohen's kappa coefficient). The area of MNF of 12 clock-hour segments and focal scleral excavation on circular scan of spectral domain optical coherence tomography were significantly correlated (P < 0.001, generalized estimating equation). The deepest direction of the circular scan was correlated with the direction of MNF vector defined as the average of the MNF direction weighted by the MNF area along 12 clock-hour segment (P < 0.036, Spearman correlation test).

Localized scleral excavation was strongly associated with the distribution of the MNF. This result indicates that the retinal areas deprived of visual stimulation by the MNF contribute to the development of axial myopia through local effects on the underlying sclera in early life.