Clinical Course of High-Frequency Millimeter-Wave (162 GHz) Induced Ocular Injuries and Investigation of Damage Thresholds

The objective was to investigate the clinical course of ocular damage and the healing process in eyes exposed to 162 GHz millimeter wave (MMW). As a 162-GHz electromagnetic wave source, a gyrotron FU CW GV was used. An ocular damaged rabbit model with good reproducibility for 162 GHz MMW exposure was developed, and damage occurrence threshold values were obtained. The right eyes of pigmented rabbits were exposed to 162 GHz from a spot-focus-type lens antenna, and the non-exposed contralateral eyes were used as control eyes. Slit-lamp examination 1 day after MMW exposure revealed a round area of opacity, characterized by fluorescein staining indicating damaged epithelial cells in the central pupillary zone. Corneal edema, indicative of corneal stromal damage, peaked 2–3 days after exposure, with thickness gradually subsiding to normal by 9 days after exposure. Power densities of 162 GHz MMW causing ocular damage with probabilities of 10, 50, and 90% obtained by probit analysis were 173, 252, and 368 mW/cm2, respectively.