RF Safe

Influence of a 902.4 MHz GSM signal on the human visual system: investigation of the discrimination threshold.

Bioelectromagnetics · 2007 · No effect · Moderate evidence

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No effectModerate evidencePaper 5055

In 33 subjects, visual discrimination threshold measured repeatedly during two 30-min sessions showed no statistically significant differences between 902.4 MHz GSM RF exposure (pulsed 217 Hz) and sham exposure.

Study snapshot

PublicationBioelectromagnetics · 2007
Study typerandomized_trial
Reported directionNo effect
Evidence ratingModerate

Abstract

The proximity of a mobile phone to the human eye raises the question as to whether radiofrequency (RF) electromagnetic fields (EMF) affect the visual system. A basic characteristic of the human eye is its light sensitivity, making the visual discrimination threshold (VDThr) a suitable parameter for the investigation of potential effects of RF exposure on the eye. The VDThr was measured for 33 subjects under standardized conditions. Each subject took part in two experiments (RF-exposure and sham-exposure experiment) on different days. In each experiment, the VDThr was measured continuously in time intervals of about 10 s for two periods of 30 min, having a break of 5 min in between. The sequence of the two experiments was randomized, and the study was single blinded. During the RF exposure, a GSM signal of 902.4 MHz (pulsed with 217 Hz) was applied to the subjects. The power flux density of the electromagnetic field at the subject location (in the absence of the subject) was 1 W/m(2), and numerical dosimetry calculations determined corresponding maximum local averaged specific absorption rate (SAR) values in the retina of SAR(1 g) = 0.007 W/kg and SAR(10 g) = 0.003 W/kg. No statistically significant differences in the VDThr were found in comparing the data obtained for RF exposure with those for sham exposure.

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 typerandomized_trial
Effect directionno_effect
PopulationHuman subjects
Sample size33
ExposureRF · 902.4 MHz · 0.007 W/kg · Two 30-min exposure periods (with 5-min break)
Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

In 33 subjects, visual discrimination threshold measured repeatedly during two 30-min sessions showed no statistically significant differences between 902.4 MHz GSM RF exposure (pulsed 217 Hz) and sham exposure.

Outcomes measured

  • Visual discrimination threshold (VDThr)
  • Light sensitivity (via VDThr)

Limitations

  • Single-blinded design (not double-blinded)
  • Power flux density reported at subject location in absence of subject; exposure at tissue level based on numerical dosimetry
View raw extracted JSON
{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 902.4,
    "sar_wkg": 0.007,
    "duration": "Two 30-min exposure periods (with 5-min break)"
  },
  "population": "Human subjects",
  "sample_size": 33,
  "outcomes": [
    "Visual discrimination threshold (VDThr)",
    "Light sensitivity (via VDThr)"
  ],
  "main_findings": "In 33 subjects, visual discrimination threshold measured repeatedly during two 30-min sessions showed no statistically significant differences between 902.4 MHz GSM RF exposure (pulsed 217 Hz) and sham exposure.",
  "effect_direction": "no_effect",
  "limitations": [
    "Single-blinded design (not double-blinded)",
    "Power flux density reported at subject location in absence of subject; exposure at tissue level based on numerical dosimetry"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency",
    "GSM",
    "902.4 MHz",
    "217 Hz pulsed",
    "visual system",
    "eye",
    "retina",
    "visual discrimination threshold",
    "sham exposure",
    "specific absorption rate"
  ],
  "suggested_hubs": []
}
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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: 10.1002/bem.20344
PubMed: 17654531

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