The fish cornea, unlike most other vertebrate corneas, is highly specialized. The first optical interface in the visual pathway, the cornea must be protective but must concomitantly act as a conduit, maximizing light transmission and maintaining effective ionic balance. Unique features include various types of light filtering mechanisms, epithelial microprojections, stromal sutures, mucus-secreting cells and protective spectacles. In keeping with the divere range of aquatic habitats infiltrated by the large number of bony and cartilaginous fishes, the cornea has adapted both structurally and physiologically. This review reveals the range of optical, structural and physiological adaptations of the fish cornea with respect to survival in a number of ecological niches. Overcoming the environmental pressures of amphibious excursions onto land, the harmful effects of short wavelength radiation in brightly-lit surface waters, the extremes of temperature and pressure in the deep-sea and the physiological effects of moving between fresh water and salt water are all examined. The anatomical nomenclature pertaining to a number of corneal structures used in early literature is also re-examined and simplified.
|Title of host publication||Sensory Biology of Jawed Fishes - New Insights|
|Editors||B.G. Kapoor, T.J. Hara|
|Publisher||Science Publishers Inc|
|Number of pages||96|
|Publication status||Published - Jan 2001|