Beyond Exposure Limits

Laser, LED & Lamp Safety

For some special products it might be necessary to consider the actual biological effects caused by exposure of the eye and the skin in the sense of the risk for injury. For this purpose we have …

  • exclusive know-how about the impact of exposure of the eye and the  skin, which we obtained through our research projects on the evaluation of retinal damage thresholds as well as through participation in committees and expert-workshops,
  • a complete data collection and bibliography of all injury thresholds that were used as the basis of setting the exposure limits,
  • fully validated simulation software for the quantitative prediction of injury thresholds in terms of thermal retinal and corneal damaging.

Our simulation software for simulating eye-damage is, above all, valuable for cases, in which the current standard IEC 60825-1 respectively the ICNIRP guidelines do not stipulate any specific rules and therefore is over-restrictive:

Scanned laser products; at the moment there are no specific rules in the IEC 60825-1 as to how the scanning of the irradiation of the retina can be accounted for; by means of our simulation-software it is possible to determine the permitted power according to scan-patterns on the retina – relative to a non-scanned case, which anchors it to the limits of the standard.

Irregular pulse sequences; at the moment there are no specific rules in IEC 60825-1 as to how pulse patterns with irregular pulse peak power can be analysed. By means of our simulation-software we are able to precisely evaluate these pulse patterns – relative to a non-scanned case, which anchors it to the limits of the standard. 

Risk analyses, in which the probability and/or the bio-effects of the radiation are characterised are especially relevant in the following cases:

  • In case of intentional exposures of the eye or the skin, in case of suppression of intrinsic eye-movements or pupil constriction -
    in these cases the limits of ICNIRP respectively IEC 60825-1 and IEC 62471 shall not be used.
  • If the limits for the eye and the skin are over-restrictive
    due to the safety factors within the limits, an exposure can be safe, even though it is above the limits. 
  • In terms of questions relating to necessary functional safety or warnings -
    When the risk is higher, an automated constructional safety-installation (functional safety by engineering means) will become necessary, when the risk is lower, a warning can be sufficient.
  • If the reliability of safety-installations matters -
    the higher the risk, the higher the need for a reliable safety-installation (SIL factor according to IEC 61508).
  • In terms of a classification according to the IEC 60825-1 standard, single fault conditions have to be taken into consideration –
    except in cases where the fault is considered so unlikely that it is not reasonably foreseeable – for which the principles of risk analysis are applied and IEC 61508 is referenced  – the more severe the possible damage and the higher the probability of exposure, the smaller the fault rate has to be (to be considered as not reasonably foreseeable).
  • If the risk of eye-damage has to be quantified regarding damage probability -
    for this purpose it is essential to calculate the exposure probability as well as the corresponding extent of the exposure. It is also necessary to consider the biological damage threshold. 
  • For questions regarding liability–
    First of all, risk for liability only exists when the product can actually cause an injury – which can be assessed based on injury thresholds. Secondly, if an injury occurred, a manufacturer is only liable when the product is considered “defective”, which means it did not feature the level of safety as generally expected. These questions are assessed virtually independent of any technical standards (see e-book in German).


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