Magoon E H, Robb R M
Arch Ophthalmol. 1981 Apr;99(4):655-9. doi: 10.1001/archopht.1981.03930010655011.
The early development of myelin in human optic nerve and tract was studied in plastic-embedded material from post-mortem examinations of 18 infants and children. Specimens were examined by light and electron microscopy, and a good correlation was found between the data obtained by the two techniques. The characteristic lamellae of myelin were first seen around a few fibers of tract and intracranial optic nerve at 32 weeks of gestation. By term, these myelin sheaths had become thicker, and a majority of the nerve fibers had become myelinated. In the optic nerve near the globe, myelin was first seen at term and virtually all fibers were myelinated by 7 months of age. Significant increases in sheath thickness were seen in the first two years, and modest increases were found thereafter. These results are in agreement with earlier observations that, in the optic nerve, myelination proceeds from the brain toward the eye. The present data suggest that a significant amount of myelination in the human optic nerve occurs after a full-term (40-week) gestation, during a period of rapid postnatal visual development.
通过对18例婴幼儿尸检获取的塑料包埋材料，研究了人类视神经和视束髓鞘的早期发育。通过光学显微镜和电子显微镜对标本进行检查，发现两种技术所获数据具有良好的相关性。髓鞘的特征性板层最早在妊娠32周时出现在视束和颅内视神经的少数纤维周围。到足月时，这些髓鞘变厚，大多数神经纤维已髓鞘化。在眼球附近的视神经中，髓鞘最早在足月时出现，到7个月大时几乎所有纤维都已髓鞘化。在出生后的头两年，髓鞘厚度显著增加，此后增加幅度较小。这些结果与早期观察结果一致，即在视神经中，髓鞘形成从脑部向眼部进行。目前的数据表明，人类视神经的大量髓鞘形成发生在足月（40周）妊娠之后，即在出生后视觉快速发育的时期。
