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ISRAELI RESEARCH: CELL PHONE RADIATION MAY CAUSE VISUAL DAMAGE In a recent scientific study conducted by a team of researchers from the Technion, a possible link between microwave radiation, similar to the ty pe found in cellular phones, and different kinds of damage to the visual system was found. At least one kind of damage seems to accumulate over time and not heal, challenging the common view and leading the researche rs to the assertion that the duration of exposure is not less important than the intensity of the irradiation. The researchers also emphasized t hat existing exposure guidelines for microwave radiation might have to c hange.
Microscope photographs of lenses incubated in organ culture conditions fo r 12 days. The effects of exposure to electromagnetic radiation have long been a sub ject for debate among scientists. The technological developments of the last twenty years such as cell and cordless phones, wireless communicati ons, monitors and even high voltage lines have all been studied as poten tial risk factors for cancer and other diseases. Less known to the publi c, but still a matter of some extensive research, is the study of the ef fect of microwave radiation on the visual system and especially on the l ens of the eye. The basic motivation for this research came after World War II when it was suspected that radar operators suffered a greater ris k of developing cataracts (a condition characterized by clouding in the natural lens of the eye). Although these particular suspicions were even tually shown to be debatable, they were the trigger for the first guidel ines for exposure to electromagnetic radiation. Moreover, the eye as our natural radiation detector is the obvious choice for investigating the effects of electromagnetic radiation upon the human body.
The electromagnetic system exposing four eye lenses to electromagnetic ra diation Each vessel containing a lens, inserted between the two plates o f the transmission line. The entire system is placed in an incubator mai ntaining constant temperature for the duration of exposure. In more recent studies on animals the effects of microwave radiation as a risk factor for cataracts have been established and have helped determi ne the guidelines put forth by the International Commission on Non-Ioniz ing Radiation Protection (ICNIRP) in 1998. A common measure for microwav e radiation is the Specific Absorption Rate (SAR) which is the average p ower density absorbed in a given volume per average weight density (Watt /Kg). This is the standard used by cell phone companies, among others, t o measure levels of radiation. When microwave energy impinges upon body tissue, part of it is absorbed and converted to heat due to ionic conduc tion. This heat manifests itself as a temperature increase inside the ti ssue. Past studies in animals have shown that even a slight increase in temperature close to the lens (as low as 3 degrees Celsius) can increase the risk of developing a cataract. With a low enough SAR the local temp erature in the lens might never increase to that level. A less common me asure is called Specific Energy Absorption (SA), and is defined as the e nergy density absorbed in the tissue divided by its weight density. Whil e SAR is the measure of the rate microwave radiation is absorbed by a ti ssue, SA is the measure of the total energy absorbed. This difference pl ayed a significant role in a recently published study on the effects of microwave radiation on the visual system. In the study conducted by researchers in the Rappaport Faculty of Medicin e at the Technion, and published in the journal Bioelectromagnetics, a n ew link has been found between microwave radiation and the development o f cataracts. Eye lenses of one-year-old male calves obtained from a slau ghterhouse were exposed to microwave radiation - one eye from each pair used for control. Both con trol and exposed lens were kept in an incubator at a constant temperatur e During this period each exposed lens had experienced up to 2mW of 11 GHz radiation virtually around the clock, and each hour it was exposed f or a 50 minute session followed by a 10 minute break. During one of thes e breaks, every 24 hours, it was tested optically and compared to the co ntrol lens. During the short (5 minutes) optical test, the lens was not exposed to radiation, but when exposed, its average temperature was main tained constant in an incubator.
Good quality lens as demonstrated by the optical scanner. All rays passin g Through the lens have similar focal length. The thick dashed line conn ects the points of the back vertex Distance for each ray passing through the lens.
Exposed lens, showing considerable variability in the focal length of the beams passing through the lens. The experiment yielded a number of interesting results: 1 Exposing the lens for a prolonged time to microwave radiation (in the frequency and intensity described above) caused macroscopic damage affec ting the optical quality of the lens. This damage increased as the exper iment and irradiation continued and reached a maximum level after a numb er of days. When the exposure stopped the optical damage began to heal g radually. Interestingly enough, a similar maximum level was observed whe n the irradiation intensity was reduced to one-half the original, except that it took twice the time. Tiny "bu bbles" were created on the surface of the lens. The bubbles were formed by irradiation with microwave and were not the result of a heat created throughout the lens. The researchers have speculated that the mechanism responsible for the creation of the bubbles is microscopic friction betw een particular cells exposed to electromagnetic radiation. Contrary to t he macroscopic damage, the microscopic damage did not show any signs of healing and continued to accumulate during the course of the experiment.
Professor Levi Schchter Although the researchers are cautious about interpreting the results of t he experiment and its possible implications to public health, it seems t hat prolonged exposure to microwave radiation similar to that used by ce llular phones can lead to both macroscopic and microscopic damage to the lens and that at least part of this damage seems to accumulate over tim e and does not seem to heal. Professor Levi Schchter, who worked on the research, told IsraCast that attention should be paid not only to the S pecific Absorption Rate (SAR) but also to the total energy absorbed by t he tissue (SA), which is not currently under supervision by the appropri ate regulative authorities. Implying that the duration of exposure is no t less important than the intensity of the irradiation.
For comments about this article, contact Iddo Genuth & Tomer Yaffe Editor: Tomer Yaffe | Word proofing & Editing by Talia Adar | Graphic Edi tor: Yael Yaffe 2005 IsraCast Jerusalem. Any reproduction or use of the materials on this website without express written permission of IsraCast is prohibited.
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