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Accession Number:
ADA172458
Title:
Mechanisms of Retinal Damage from Chronic Laser Radiation.
Descriptive Note:
Annual rept. 1 Sep 73-31 Oct 76,
Corporate Author:
LOUISVILLE UNIV KY DEPT OF OPHTHALMOLOGY
Report Date:
1976-11-01
Pagination or Media Count:
37.0
Abstract:
The effect upon the retina oif exposure to large fields of bright visible light has been evaluated. The thresholds for retinal damage for four hour exposures in rhesus monkeys have been established for white light, argon laser lines of 514.5 nm, 488 nm, and 457.9 nm, and for 590 nm light from a dye laser. The damage has been evaluated by ophthalmoscopy, electroretinography, light and electron microscopy. The 457.9 nm light is more effective in causing damage, particularly histological damage, which is spread throughout the fundus and throughout the retinal layers. Functional damage shown by the electroretinogram follows a different spectral sensitivity curve without the increased effect in the blue. There appears to be more than one mechanism for retinal damage in chronic light exposure, and at least one mechanism is not dependent upon the visual pigment or the pigment epithelium. Thresholds appear to be within one or two log units of light levels encountered in normal visual experience. In our model, we are talking about exposing most of the posterior pole to an even illumination of moderately bright light for a period of hours. We are not talking about the thermal damage caused by small spot laser burns and photocoagulation. We are showing here not onlyu7 that the threshold is lower with blue light, but that the morphological changes are different from those previously described. Primary damage occurs in retinal layers which we think of as transparent to the damaging wavelength.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
