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Revisiting 35 and 94 GHZ Millimeter Wave Exposure to the Non-human Primate Eye

2020 · Harm · Low evidence

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HarmLow evidencePaper 1508

Using improved models and dosimetry, corneal exposure data agreed with a three-layer, one-dimensional thermodynamic model predicting surface temperature rise. The study reports that previously reported safety margins for eye exposures were underestimated by 4…

Study snapshot

Publicationmanual · 2020
Study typeanimal
Reported directionHarm
Evidence ratingLow

Abstract

Revisiting 35 and 94 GHZ Millimeter Wave Exposure to the Non-human Primate Eye James E Parker, Charles W Beason, Stephen P Sturgeon, William B Voorhees, Samuel S Johnson, Kaitlin S Nelson, Leland R Johnson, Jeffrey N Whitmore. Revisiting 35 and 94 GHZ Millimeter Wave Exposure to the Non-human Primate Eye. Health Phys. 2020 Jun 3. doi: 10.1097/HP.0000000000001216. Abstract A previous study reported thermal effects resulting from millimeter wave exposures at 35 and 94 GHz on non- human primates, specifically rhesus monkeys' (Macaca mulatta) corneas, but the data exhibited large variations in the observed temperatures and uncertainties in the millimeter wave dosimetry. By incorporating improvements in models and dosimetry, a non-human primate experiment was conducted involving corneal exposures that agreed well with a three-layer, one-dimensional, thermodynamic model to predict the expected surface temperature rise. The new data indicated that the originally reported safety margins for eye exposures were underestimated by 41 ± 20% over the power densities explored. As a result, the expected minimal visible lesion thresholds should be raised to 10.6 ± 1.5 and 7.1 ± 1.0 J cm at 35 and 94 GHz, respectively, provided that the power density is less than 6 W cm for subjects that are unable to blink. If the blink reflex was active, a power density threshold of 20 W cm could be used to protect the eye, although the eyelid could be burned if the exposure was long enough. pubmed.ncbi.nlm.nih.gov

Machine Enhanced Logic

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
PopulationNon-human primates (rhesus monkeys; Macaca mulatta)
Sample sizeNot supplied
ExposuremmWave
Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Using improved models and dosimetry, corneal exposure data agreed with a three-layer, one-dimensional thermodynamic model predicting surface temperature rise. The study reports that previously reported safety margins for eye exposures were underestimated by 41 ± 20% over the explored power densities, and proposes raising minimal visible lesion thresholds to 10.6 ± 1.5 and 7.1 ± 1.0 J/cm at 35 and 94 GHz, respectively, under specified power-density and blinking conditions.

Outcomes measured

  • Corneal surface temperature rise (thermal effects)
  • Visible lesion threshold estimates for eye exposure
  • Safety margin estimates for eye exposures
  • Power density thresholds related to blink reflex/eye protection
  • Potential eyelid burns with prolonged exposure

Limitations

  • Sample size not reported in the provided abstract/metadata
  • Exposure duration and detailed exposure conditions are not fully specified in the provided abstract
  • Findings are based on non-human primate eye exposures; generalizability to humans is not stated in the provided abstract
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "mmWave",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Non-human primates (rhesus monkeys; Macaca mulatta)",
  "sample_size": null,
  "outcomes": [
    "Corneal surface temperature rise (thermal effects)",
    "Visible lesion threshold estimates for eye exposure",
    "Safety margin estimates for eye exposures",
    "Power density thresholds related to blink reflex/eye protection",
    "Potential eyelid burns with prolonged exposure"
  ],
  "main_findings": "Using improved models and dosimetry, corneal exposure data agreed with a three-layer, one-dimensional thermodynamic model predicting surface temperature rise. The study reports that previously reported safety margins for eye exposures were underestimated by 41 ± 20% over the explored power densities, and proposes raising minimal visible lesion thresholds to 10.6 ± 1.5 and 7.1 ± 1.0 J/cm at 35 and 94 GHz, respectively, under specified power-density and blinking conditions.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in the provided abstract/metadata",
    "Exposure duration and detailed exposure conditions are not fully specified in the provided abstract",
    "Findings are based on non-human primate eye exposures; generalizability to humans is not stated in the provided abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "millimeter wave",
    "35 GHz",
    "94 GHz",
    "eye",
    "cornea",
    "rhesus monkey",
    "Macaca mulatta",
    "thermal effects",
    "dosimetry",
    "thermodynamic model",
    "power density",
    "lesion threshold",
    "blink reflex"
  ],
  "suggested_hubs": [
    {
      "slug": "5g-policy",
      "weight": 0.62,
      "reason": "Millimeter-wave (35 and 94 GHz) exposure and eye safety thresholds are relevant to mmWave discussions often associated with 5G."
    }
  ]
}
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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: 10.1097/hp.0000000000001216
PubMed: 32501817

Read the original paper →

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