ID Number		653
Study Type		In Vivo
Model		6-200 MHz, 1.25, 35-94 GHz (PW) exposure to monkeys and analysis of eye damage
Details		Rhesus monkeys were exposed to 1.25 GHz (PW- 5.59 us pulse length, 0, 0.59, 1.18, and 2.79 Hz pulse repetition rates) for 4 hr/day, 3 days/week, for 3 weeks at SARs of at 0, 4.3, 8.4, or 20.2 W/kg. No effect of exposure was observed by retinal histopathology (presence of enhanced glycogen storage in photoreceptors), although supranormal cone photoreceptor b-wave was affected by exposure at 8 W/kg or above, and the authors suggest this may be an early indicator of mild injury. The authors concluded that retinal injury is unlikely at 4 W/kg or below. In other studies, monkeys were exposed to 6-200 MHz and 35-94 GHz at increasing SAR levels of up to 20 W/kg for various times in the near field and analyzed for retinal and lens pathology. No effects were observed in monkeys even at the highest exposure levels. In rabbits, exposure to 150 mW/m2 for 100 minutes did result cataracts. The authors suggest it is more difficult to couple energy into the monkey skull than the rabbit skull. Attempts at replicating reports of optical damage by Kues et al following extended exposure of rabbits to 1.25 GHz at 4.2 W/kg were not successful, even when exposure levels were increased 20 W/kg using 1-10 GHz frequencies. AUTHORS' ABSTRACT: Chalfin et al. 2002 (IEEE #7075): The purpose of this study was to evaluate anterior segment bioeffects of pulsed 35 GHz and 94 GHz microwave exposure in the nonhuman primate eye. Five juvenile rhesus monkeys (Macaca mulatta) underwent baseline anterior segment ocular assessment consisting of slit lamp examination, corneal topography, specular microscopy, and pachymetry. These studies were repeated after exposure of one eye to pulsed 35 GHz or 94 GHz microwaves at varied fluences, with the other eye serving as a control. The mean fluence required to produce a threshold corneal lesion (faint epithelial edema and fluorescein staining) was 7.5 J cm 2 at 35 GHz and 5 J cm 2 at 94 GHz. Transient changes in corneal topography and pachymetry were noted at these fluences. Endothelial cell counts remained unchanged. Threshold corneal injury from 35 GHz and 94 GHz microwave exposure is produced at fluences below those previously reported for CO2 laser radiation. These data may help elucidate the mechanism of thermal injury to the cornea, and resolve discrepancies between IEEE C95.1 (1999), NCRP (1986), and ICNIRP (1998) safety standards for exposure to non-ionizing radiation at millimeter wavelengths.
Findings		Effects (only at thermal levels)
Status		Completed With Publication
Principal Investigator		USAF Research Lab, Brooks AF Base, USA - shin-tsu.lu@afrlars.brooks.af.mil
Funding Agency		AF, USA
Country		UNITED STATES
References		Lu, ST et al. Bioelectromagnetics, (2000) 21:439-454 Lu, ST et al. Bioelectromagnetics., (2010) 31:324-333 Chalfin, S et al. Health Phys., (2002) 83:83-90
Comments		The above studies could not replicate the findings of Kues et al. The authors suggest this is due to the lack of high peak pulse power in their RF signal as was used in the Kues et al study. In terms of RF signal emitted by cell phones, this would indicate that there is not enough energy for corneal, retinal, or other eye damage.