Ocular Effects of Exposure to 40, 75, and 95 GHz Millimeter Waves

2018 · Harm · Moderate evidence

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HarmModerate evidencePaper 1679

Study snapshot

Publicationmanual · 2018

Study typeanimal

Reported directionHarm

Evidence ratingModerate

Abstract

Ocular Effects of Exposure to 40, 75, and 95 GHz Millimeter Waves Kojima M, Suzuki Y, Sasaki K,Taki M, Wake K, Watanabe S, Mizuno M, Tasaki T, Sasaki H. Ocular Effects of Exposure to 40, 75, and 95 GHz Millimeter Waves. Journal of infrared, millimeter and terahertz waves. 39(9):912-925. DOI: 10.1007/s10762-018-0497-z Abstract The objective of this study was to develop a model of ocular damage induced by 40, 75, and 95 GHz continuous millimeter waves (MMW), thereby allowing assessment of the clinical course of ocular damage resulting from exposure to thermal damage-inducing MMW. This study also examined the dependence of ocular damage on incident power density. Pigmented rabbit eyes were exposed to 40, 75, and 95 GHz MMW from a spot-focus- type lens antenna. Slight ocular damage was observed 10 min after MMW exposure, including reduced cornea thickness and reduced transparency. Diffuse fluorescein staining around the pupillary area indicated corneal epithelial injury. Slit-lamp examination 1 day after MMW exposure revealed a round area of opacity, accompanied by fluorescence staining, in the central pupillary zone. Corneal edema, indicative of corneal stromal damage, peaked 1 day after MMW exposure, with thickness gradually subsiding to normal. Three days after exposure, ocular conditions had almost normalized, though corneal thickness was slightly greater than that before exposure. The 50% probability of ocular damage (DD50) was in the order 40 > 95 ≈ 75 GHz at the same incident power densities. Conclusion We created rabbit models of ocular disorder by exposure to 40, 75, and 95 GHz MMW. In assessing the relationship between the degree of ocular disorder and incident power density of these three frequencies, we found that ocular damage induced by exposure to 40, 75, and 95 GHz was essentially the same, with no characteristic specific to each frequency. We also found that corneal surface temperature during exposure was increased in the order 40 < 95 < 75 GHz, but there was no relationship between degree of ocular damage and eye surface temperature. In addition, we performed probit analyses by using experimental data and estimated probabilities for incidence of ocular damage depending on the power density. DD50, defined as dose level to cause ocular damage with 50% probability, was in the order 40 GHz (206 mW/cm2) > 95 GHz (146 mW/cm2) ≈ 75 GHz (143 mW/cm2). At the same incident power density, the degree of ocular damage was greater in the eyes exposed for 30 min than for 6 min. These findings suggested that damage to the corneal epithelium was not induced by corneal dryness alone, but by exposure of dried corneas to MMW-induced heat to above body temperature. Open access paper: link.springer.com

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal

Effect directionharm

Populationpigmented rabbit eyes

Sample sizeNot supplied

ExposuremmWave · 6 to 30 minutes

Evidence strengthModerateConfidence: 70% · Peer reviewed: yes

Main findings

Exposure to 40, 75, and 95 GHz millimeter waves induced slight ocular damage in pigmented rabbit eyes, including corneal epithelial injury and edema. The degree of damage was similar across frequencies, with damage increasing with exposure duration. The 50% probability dose (DD50) was highest at 40 GHz and lower at 75 and 95 GHz. Corneal surface temperature changes did not correlate with damage severity.

Outcomes measured

reduced cornea thickness
reduced transparency
corneal epithelial injury
corneal edema
ocular damage probability (DD50)

Limitations

Animal model may not fully represent human ocular effects
Sample size not specified
Only short-term effects assessed

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "mmWave",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "6 to 30 minutes"
  },
  "population": "pigmented rabbit eyes",
  "sample_size": null,
  "outcomes": [
    "reduced cornea thickness",
    "reduced transparency",
    "corneal epithelial injury",
    "corneal edema",
    "ocular damage probability (DD50)"
  ],
  "main_findings": "Exposure to 40, 75, and 95 GHz millimeter waves induced slight ocular damage in pigmented rabbit eyes, including corneal epithelial injury and edema. The degree of damage was similar across frequencies, with damage increasing with exposure duration. The 50% probability dose (DD50) was highest at 40 GHz and lower at 75 and 95 GHz. Corneal surface temperature changes did not correlate with damage severity.",
  "effect_direction": "harm",
  "limitations": [
    "Animal model may not fully represent human ocular effects",
    "Sample size not specified",
    "Only short-term effects assessed"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.7,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "millimeter waves",
    "ocular damage",
    "corneal injury",
    "40 GHz",
    "75 GHz",
    "95 GHz",
    "thermal effects"
  ],
  "suggested_hubs": [
    {
      "slug": "mmwave-exposure",
      "weight": 0.9,
      "reason": "Study focuses on ocular effects of millimeter wave exposure at 40, 75, and 95 GHz."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1007/s10762-018-0497-z
PubMed: Not supplied

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