Progression of retinal nerve fiber myelination in childhood.

Myelination of the visual pathway has been demonstrated to occur by as early as 32 weeks of gestation and continues for several years into early childhood. In most cases, the process of myelination does not extend beyond the lamina cribrosa. We studied a boy with progressive myelination that extended beyond the lamina cribrosa to the retinal nerve fibers. Ocular examination at 15 months of age disclosed myelinated optic nerve fibers of the right eye. We repeated examination every two to six months and found progression of the extent and density of the myelinated nerve fibers. Despite the marked myelination, the patient did not experience a decrease in visual acuity.