A comparative SEM study of the vertebrate corneal epithelium

Collin, Shaun P. and Collin, H. Barry (2000) A comparative SEM study of the vertebrate corneal epithelium. Cornea, 19 2: 218-230. doi:10.1097/00003226-200003000-00017

Author Collin, Shaun P.
Collin, H. Barry
Title A comparative SEM study of the vertebrate corneal epithelium
Journal name Cornea   Check publisher's open access policy
ISSN 0277-3740
Publication date 2000-03
Sub-type Article (original research)
DOI 10.1097/00003226-200003000-00017
Volume 19
Issue 2
Start page 218
End page 230
Total pages 13
Place of publication New York
Publisher Lippincott Williams & Wilkins
Language eng
Subject C1
06 Biological Sciences
1109 Neurosciences
Formatted abstract
The anterior surface of the cornea of mammals, including humans, has numerous folds in the anterior epithelial cell membranes in the form of microvilli and microplicae. The role of these surface irregularities may be to increase cell-surface area and therefore aid in intra- and extracellular movement of nutritional and waste products across the cell membranes in addition to stabilizing the corneal tear film. The aim of this study was to investigate and compare the nature of these corneal-surface features in various vertebrate classes residing in different environments.

The anterior corneal surfaces of various vertebrates were investigated by using field emission scanning electron microscopy. Cell areas were analyzed by using image-analysis software.


Representative species were examined from all the vertebrate classes, with the exception of the Cephalaspidomorphi. The mean epithelial cell density of aquatic vertebrates (17,602 +/- 9,604 cells/mm(2)) is greater (p = 0.000018) than that of aerial and terrestrial vertebrate species, including amphibians (3,755 +/- 2,067 cells/mm(2)). Similarly, the mean epithelial cell density for the marine vertebrates (22,553 +/- 8,878 cells/mm(2)) is greater (p = 0.0015) than that of the freshwater and estuarine species (10,529 +/- 5,341 cells/mm(2)). The anterior corneal surfaces of all species examined were found to show a variety of cell-surface structures. Microvilli are predominant in reptiles, birds, and mammals; microridges appear to be characteristic of the Osteichthyes; and microholes were observed only in the Chondrichthyes.

The function of these morphologic variations in surface structure appear to be correlated with the range of ecologic environments (marine. aerial. and terrestrial) occupied by each species, corneal phylogeny, and the demands placed on the cornea to ensure clear vision.
Keyword Ophthalmology
Scanning Electron-microscopy
Oral Mucosal Epithelium
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biomedical Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 18 times in Thomson Reuters Web of Science Article | Citations
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Created: Mon, 13 Aug 2007, 11:38:50 EST