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M. Kojima, Y. Yamashiro, M. Hanazawa, S. Watanabe, H. Sasaki, M. Taki, K. Sasaki; Investigation of Frequency Specificity of Ocular Effects Through Quasi-Millimeter and Millimeter Wave Exposure. Invest. Ophthalmol. Vis. Sci. 2007;48(13):395.
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© ARVO (1962-2015); The Authors (2016-present)
The validity of limit exposure guidelines of 3-300 GHz (10 mW/cm2) for a quasi-millimeter and a millimeter wave was examined with ocular temperature changes during exposure and ocular injury after exposure.
Pigmented rabbits were exposed unilaterally to an 18, 22, 26.5 GHz or 26.5, 35, 40 GHz quasi- and millimeter-wave with lens antenna for 3 minutes. The same average incident power for each frequency was exposed to the center of the rabbit cornea. Both forward and reverse powers were monitored with a power meter. Ocular temperature changes (cornea, lens, vitreous, retrobulbar) during a 3 min. exposure were measured with a Fluoroptic thermometer and corneal surface temperature was measured with a thermometer. For evaluating ocular injury, a rabbit was exposed to one frequency (18, 22, 26.5, 35, 40 GHz) with 800 mW/cm2 for 6 min. Ocular changes were evaluated by slit lamp and ocular inflammation was measured by laser flare meter immediately after and 1 day after exposure.
Cornea and lens temperature rise were detected by exposure with all examined frequencies. The highest ocular and corneal surface temperature was 40 GHz, followed by 35, 22 and 18 (almost the same), and the lowest was 26.5 GHz. Ocular injury by 800 mW/cm2 for 6 min. exposure was seen only with 40 GHz. Miosis and iris vasodilation were seen immediately after exposure, and corneal epithelial defect at the center of the cornea and corneal opacity were seen one day after exposure.
It was suggested that thermal and biological reactions differed according to frequency, even when the average incident power was the same.
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