Biomaterial Database

The effect of regional retinal photocoagulation on vitreal oxygen tension. 1987

V A Alder, and S J Cringle, and M Brown

PO2 measurements have been made for the first time within the retina and vitreous of cat eyes to compare normal and photocoagulated areas. This was done to test the hypothesis that the observed beneficial effects of pan-retinal photocoagulation therapy in the treatment of retinal vascular diseases with an ischemic origin, may be due to more oxygen becoming available to the remaining functioning retina. A xenon arc photocoagulator was used to photocoagulate large areas of cat retinas served by one major set of vessels while leaving the remaining retina untouched. After 6 months an acute experiment was performed in which retinal and vitreal oxygen tension profiles were measured using oxygen-sensitive microelectrodes to compare PO2 profiles in normal and photocoagulated regions, for two ventilation conditions: air and 100% O2. The only differences in PO2 values were found for the 100% O2 breathing condition, where values within the retina and in the overlying vitreous were larger in photocoagulated areas. It is proposed that any differences in PO2 distribution which occur for air breathing are masked by the autoregulatory capacity of the retinal circulation and the PO2 buffering capacity of hemoglobin.

UI	MeSH Term	Description	Entries
D008028	Light Coagulation	The coagulation of tissue by an intense beam of light, including laser (LASER COAGULATION). In the eye it is used in the treatment of retinal detachments, retinal holes, aneurysms, hemorrhages, and malignant and benign neoplasms. (Dictionary of Visual Science, 3d ed)	Photocoagulation,Coagulation, Light,Coagulations, Light,Light Coagulations,Photocoagulations
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D010313	Partial Pressure	The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Partial Pressures,Pressure, Partial,Pressures, Partial
D010865	Pilot Projects	Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.	Pilot Studies,Pilot Study,Pilot Project,Project, Pilot,Projects, Pilot,Studies, Pilot,Study, Pilot
D011184	Postoperative Period	The period following a surgical operation.	Period, Postoperative,Periods, Postoperative,Postoperative Periods
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
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
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
D014822	Vitreous Body	The transparent, semigelatinous substance that fills the cavity behind the CRYSTALLINE LENS of the EYE and in front of the RETINA. It is contained in a thin hyaloid membrane and forms about four fifths of the optic globe.	Vitreous Humor,Bodies, Vitreous,Body, Vitreous,Humor, Vitreous,Humors, Vitreous,Vitreous Bodies,Vitreous Humors