Corneal epithelium and UV-protection of the eye.
OBJECTIVE
To study UV-absorption and UV-induced fluorescence in the bovine corneal epithelium.


METHODS
Spectrophotometry and spectrofluorimetry.


RESULTS
The corneal epithelium absorbs UV-B radiation mainly owing to its content of protein, RNA, and ascorbate. Some of the absorbed energy is transformed to the less biotoxic UV-A radiation by fluorescence. RNA and ascorbate reduce tissue fluorescence.


CONCLUSIONS
The corneal epithelium acts as a UV-filter, protecting internal eye structures through three different mechanisms: (1) Absorption of UV-B roughly below 310 nm wavelength. (2) Fluorescence-mediated ray transformation to longer wavelengths. (3) Fluorescence reduction. The extremely high ascorbate concentration in the corneal epithelium has a key role in two of these processes.
Ringvold
A
A
University Eye Department, National Hospital Oslo, Norway.
D000042:Absorption; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002417:Cattle; D003315:Cornea / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects*; D005453:Fluorescence; D005470:Fluorometry; D005978:Glutathione / Q000494:pharmacology; D012313:RNA / Q000494:pharmacology; D013053:Spectrophotometry; D014364:Tryptophan / Q000494:pharmacology; D014466:Ultraviolet Rays
D012313:RNA; D014364:Tryptophan; D005978:Glutathione; D001205:Ascorbic Acid