Determination of ocular threshold levels for infrared radiation cataractogenesis.
Pitts-DG; Cullen-AP; Dayhaw-Barker-P; Moss-CE Jr.
College of Optometry, University of Houston :61 pages
Ocular threshold exposure values for infrared radiation (IR) needed to produce cataracts in rabbit and monkey eyes were measured. A 5000 Watt Xenon high pressure lamp was used to expose 100 pigmented rabbit eyes and 10 monkey eyes to IR. The primary ocular lesion consisted of an epithelial subcapular opacity induced by IR exposure, appearing as small whitish dots that developed into white patches in the anterior capsule in contact with the iris. Lenticular opacities were caused by exposure to the lens. Ocular damage was related to the rate of radiation delivery. Irradiances up to 3.9 watts per square centimeter resulted in thresholds for the rabbit eye of 5000 joules per square centimeter (J/cm2) for the cornea, .3500J/cm2 for the iris and 3750J/cm2 for the lens. Irradiances above 4.0J/cm2 gave rabbit, ocular thresholds of 1250J/cm2 for the, cornea and iris and 2250J/cm2 for the lens. The authors note that optical spectrum exposure of the source indicated that the visible and ultraviolet radiation were additive for lens damage. They conclude that the monkeys' ocular thresholds were a factor of 6 above the respective rabbits' threshold.
NIOSH-Contract; Contract-210-77-0042; Eye-function-tests; Exposure-methods; Infrared-radiation; Eye-disorders; Laboratory-animals; High-pressure; Analytical-methods;
Division of Biochemical and Behavioral Science
College of Optometry University of Houston Houston, TX