Search Results

6.Transitional Zone of the Corneal Endothelium: Flat Preparation and Ultrastructural Findings.

O Sub KOO ; Myung Kyoo KO

Journal of the Korean Ophthalmological Society 2007;48(5):691-698

PURPOSE: To evaluate the morphological characteristics of the transitional zone between the corneal endothelium and the trabecular meshwork by flat preparation and electron microscopy. METHODS: The materials comprised 12 eyes examined by the flat preparation and 7 eyes by the electron microscopy. The specimens were derived from the transitional tissue between the corneal endothelium and the trabecular meshwork. The specimens in the flat preparation were stained with hematoxylin-eosin and examined by light microscopy. The specimens for scanning electronic microscopy (SEM) and in transmission electronic microscopy (TEM) were examined through routine processes. RESULTS: In the specimens examined by the flat preparation, unlike peripheral corneal endothelial cells, the endothelial cell nuclei in the transitional zone were overlapped and morphologically oval. On SEM, unlike typical hexagonality and tight interdigitation of corneal endothelial cells, the endothelial cells in the transitional zone were partially successive, spaced intercellularly, and morphologically irregular. On TEM, the endothelial cells in the transitional zone were partially successive. CONCLUSIONS: The loss of cell-cell contact of endothelial cells in the transitional zone may lead to the potential proliferation capacity of endothelial cells in the transitional zone under specific conditions. Therefore, further studies on the proliferation capacity of endothelial cells in the transitional zone are needed together with more research on cell biology.
Endothelial Cells ; Endothelium, Corneal* ; Microscopy ; Microscopy, Electron ; Trabecular Meshwork

7.Morphological Characteristics and Intercellular Connections of Corneal Keratocytes.

Gu Min KANG ; Myung Kyoo KO

Korean Journal of Ophthalmology 2005;19(3):213-218

PURPOSE: To investigate the morphological characteristics of keratocytes and the interconnection of keratocytes with adjacent keratocytes using the flat preparation method and scanning electron microscopy with a frontal section of the human corneal stroma. METHODS: The thin, corneal collagen lamellae were carefully dissected from the cornea (n=7), which had been stained by the flat preparation method. The remaining tissue was fixed in 3% glutaraldehyde and observed by transmission electron microscopy following the frontal section. RESULTS: The flat preparation revealed the corneal fibroblasts between the lamellae of the collagen fibers and showed that the ramifying cellular processes of the keratocytes were in contact with the cytoplasmic processes or cell bodies of neighboring fibroblasts. Two types of discrete subpopulations of keratocytes were identified: a smaller, cellular type of keratocyte with spindle-shaped nucleus with heterochromatin, and a larger, cellular type with a large indented nucleus with relatively scanty cytoplasm. Collagen fibers ran parallel to each other toward the fenestration of the cytoplasmic wall of the keratocyte. CONCLUSIONS: These flat preparation method results showed that the keratocytes within the corneal stroma are interconnected with the adjacent keratocytes, which indicates the presence of a functional communicating network through the keratocyte circuits within the stroma. A smaller, cellular type of keratocyte with spindle-shaped nucleus was morphologically differentiated from a larger, cellular type with a large, indented nucleus by flat preparation and transmission electron microscopy.
Middle Aged ; Microscopy, Electron, Transmission ; Microscopy, Electron, Scanning ; Intercellular Junctions/*ultrastructure ; Infant ; Humans ; Corneal Stroma/*cytology/pathology ; Child, Preschool ; Child ; Cell Size ; Aged ; Adult ; Adolescent