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Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.

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Absence of Ocular Pathology after Repeated Exposure of Unanesthetized Monkeys to 9.3-GHz Microwaves

No Effects Found

R.D. McAfee, A. Longacre Jr., R.R. Bishop, S.T. Elder, J.G. May, M.G. Holland, R. Gordon · 1979

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Monkeys exposed to intense 9.31 GHz microwaves showed no eye damage, but this doesn't address today's chronic low-level wireless exposure concerns.

Plain English Summary

Summary written for general audiences

Researchers trained 12 monkeys to expose their faces and eyes to 9.31 GHz microwave radiation at 150 mW/cm² for 30-40 sessions, then monitored them for one year. No eye damage or cataracts developed from this high-frequency microwave exposure. This study examined whether microwave radiation at frequencies used in some radar and communication systems could cause eye injury.

Cite This Study
R.D. McAfee, A. Longacre Jr., R.R. Bishop, S.T. Elder, J.G. May, M.G. Holland, R. Gordon (1979). Absence of Ocular Pathology after Repeated Exposure of Unanesthetized Monkeys to 9.3-GHz Microwaves.
Show BibTeX
@article{absence_of_ocular_pathology_after_repeated_exposure_of_unanesthetized_monkeys_to_g5317,
  author = {R.D. McAfee and A. Longacre Jr. and R.R. Bishop and S.T. Elder and J.G. May and M.G. Holland and R. Gordon},
  title = {Absence of Ocular Pathology after Repeated Exposure of Unanesthetized Monkeys to 9.3-GHz Microwaves},
  year = {1979},
  
  
}

Quick Questions About This Study

This study found no cataracts in 12 monkeys exposed to 9.31 GHz microwaves at 150 mW/cm² over 30-40 sessions and monitored for one year. However, this was acute high-level exposure, not chronic low-level exposure like modern wireless devices.
The 150 mW/cm² power density used in this monkey study is approximately 1,500 times higher than typical cell phone exposure levels near your head, which range from 0.1 to 1 mW/cm² during calls.
Researchers used operant conditioning to train unanesthetized monkeys to voluntarily position their heads in the microwave field. This allowed for controlled, repeated exposures while avoiding the complications of anesthesia that might interfere with biological responses.
9.31 GHz falls between current WiFi frequencies (around 5 GHz) and some newer 5G millimeter wave bands (24-28 GHz). It's higher than most consumer wireless devices but used in some radar and satellite communication systems.
The 12 monkeys were observed for one full year after completing their 30-40 microwave exposure sessions. This observation period was designed to detect delayed effects like cataract formation, which can develop weeks or months after radiation exposure.