Accession Number : ADA140131

Title :   Mechanisms of Retinal Damage from Chronic Laser Radiation; Thresholds and Mechanisms.

Descriptive Note : Annual rept. 1 Nov 76-30 Jun 80,


Personal Author(s) : Lawwill,T ; Crockett,R S ; Currier,G

PDF Url : ADA140131

Report Date : Jun 1980

Pagination or Media Count : 42

Abstract : The effect upon the retina of exposure to large fields of bright visible light has been evaluated. The thresholds for permanent retinal damage for 4, 1, and 0.25 hour exposures in rhesus or cynomolgus monkeys have been established for laser lines of 514.5 nm, 488 nm, 457.9 nm, and 590 nm. In addition, the effect of distributing the 4 hour exposures in one hour doses separated by intervals of one day or one week has been studied. The damage has been evaluated by opthalmoscopy, electroretinography, fluorescein angiography and light and electron microscopy. The shortest wavelength light (457.9 nm) is more effective in causing damage, particularly histological damage, which is spread throughout the fundus and throughout the retinal layers. There appears to be more than one mechanism for retinal damage in chronic light exposure, and at least one mechanism is not dependent solely upon the visual pigment and the pigment epithelium. The results from our studies suggest that with relatively low intensity, long duration exposures that there is a lack of reciprocity between exposure duration and irradiance level.

Descriptors :   *Radiation effects, *Laser radiobiology, *Retina, Laser damage, Radiation damage, Rhesus monkeys, Threshold effects, Pigments, Epithelium

Subject Categories : Radiobiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE