Electron Microscopic Study of the Corneal Nerve by Flat Serial Section.
- Author:
Chang Eun BACK
1
;
Yoon Jung SONG
;
Myung Kyoo KO
Author Information
1. Kuri Eye Clinic, Kyonggi-do, Korea.
- Publication Type:Original Article
- Keywords:
Corneal nerve;
Keratocyte;
Myelinated nerve fiber;
Ultrastructure;
Unmyelinated nerve fiber
- MeSH:
Collagen;
Cornea;
Cytoplasm;
Eye Banks;
Glycogen;
Humans;
Intercellular Signaling Peptides and Proteins;
Metabolism;
Mitochondria;
Myelin Sheath;
Nerve Fibers;
Nerve Fibers, Myelinated;
Nerve Fibers, Unmyelinated;
Peripheral Nerves;
Retinoblastoma;
Sympathetic Nervous System
- From:Journal of the Korean Ophthalmological Society
2001;42(6):865-870
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: This study was performed to describe the ultrastructure of stromal nerve fibers in central, mid-peripheral, and peripheral parts of the human cornea by flat serial corneal section. METHODS: Seven samples from fresh normal cornea, derived from eyes with retinoblastoma and eyes from eye bank, were processed for transmission electron microscopic examinations. Flat serial sections reaching from mid-epithelium to the anterior stroma were observed. RESULTS: The myelinated and unmyelinated nerve fibers are alternately arranged and run parallel to the stromal collagen fibers at the periphery of the cornea. The main difference between the limbal and the central cornea is the presence of myelinated nerve fibers in the anterior peripheral stroma. The diameter of the unmyelinated nerve fiber measures between 0.25 and 0.63 micrometer in size. The corneal nerve fibers contain vesicles, mitochondria, and glycogen particles. The peripheral nerve fibers contain both clear and dense vesicles. The nerve fiber is separated by an interval of 0.3 micrometer from the cytoplasmic wall of keratocyte at the center of the cornea. CONCLUSIONS: The majority of the corneal nerve fibers can be classified as C-fibers due to their size. The presence of both clear and dense vesicles within the cytoplasm of the periphery of the cornea suggest that a small portion in the peripheral corneal nerve may be originated from the sympathetic nervous system. A close vicinity between the nerve fibers and keratocyte supports that nerve fibers might modulate the release of growth factors in the regulation of stromal and epithelial metabolism.
