Determination of Ocular Threshold Levels for Infrared Radiation Cataractogenesis

摘要

Threshold values for ocular exposure to infrared radiation (IR) were determined in ocular structures. Rabbit and monkey eyes were exposed to 700 to 1400 namometer (nm) wavelength IR for 15 minutes to 8 hours using a 5,000 watt Xenon high pressure lamp. Corneal, iris, and lenticular lesions resulted from IR test exposures. The lenticular opacities appeared as white dots at the level of the anterior epithelium beneath the anterior capsule and did not result from direct lens exposure. The rate of IR delivery determined ocular damage. Thresholds were 5,000, 3,500 and 3,750 joules per squared centimeter (J/CM2) for rabbit cornea, iris, and lens, respectively, at 3.9 watts per square centimeter (W/CM2) irradiances. Damage to the lens was additive with exposure to visible and ultraviolet radiation. The primate threshold radiant exposure exceeded respective rabbit thresholds by a factor of six. The authors recommend that protective glasses have metallic coatings and absorptive filters to protect against IR exposure and heating of protective lens. Additional research on acute and chronic exposure effects and the correlation between rate of delivery and cataractogenesis is suggested.