Biomaterial Database

The corneal contact lens and aqueous humor hypoxia in cats. 1983

E Stefansson, and M L Wolbarsht, and M B Landers

The cornea normally receives its oxygen from both the atmosphere and the aqueous humor. When a thick polymethylmethacrylate contact lens is placed on the cat cornea, access of atmospheric oxygen to the cornea is restricted, and the outer part of the cornea becomes hypoxic. This results in an increase in the oxygen flux from the aqueous humor into the cornea, and the oxygen tension in the aqueous humor decreases, as is demonstrated in this study. This increased oxygen flux from the aqueous into the cornea tends to alleviate the hypoxia caused by a corneal contact lens. Thus, the cornea can tolerate a thicker contact lens with less hypoxia than would be expected if only the oxygen supply from the atmosphere were considered.

UI	MeSH Term	Description	Entries
D007429	Intraocular Pressure	The pressure of the fluids in the eye.	Ocular Tension,Intraocular Pressures,Ocular Tensions,Pressure, Intraocular,Pressures, Intraocular,Tension, Ocular,Tensions, Ocular
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D003261	Contact Lenses	Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)	Lenses, Contact,Contact Lens,Lens, Contact
D003315	Cornea	The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)	Corneas
D005128	Eye Diseases	Diseases affecting the eye.	Eye Disorders,Eye Disease,Eye Disorder
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000860	Hypoxia	Sub-optimal OXYGEN levels in the ambient air of living organisms.	Anoxia,Oxygen Deficiency,Anoxemia,Deficiency, Oxygen,Hypoxemia,Deficiencies, Oxygen,Oxygen Deficiencies
D001082	Aqueous Humor	The clear, watery fluid which fills the anterior and posterior chambers of the eye. It has a refractive index lower than the crystalline lens, which it surrounds, and is involved in the metabolism of the cornea and the crystalline lens. (Cline et al., Dictionary of Visual Science, 4th ed, p319)	Aqueous Flare,Intraocular Fluid,Aqueous Flares,Aqueous Humors,Flare, Aqueous,Fluid, Intraocular,Fluids, Intraocular,Humor, Aqueous,Humors, Aqueous,Intraocular Fluids