Webinar: Lens of the eye

The Canadian Nuclear Safety Commission (CNSC) and the Canadian Radiation Protection Association (CRPA) hosted a webinar on March 21, 2018 on the scientific basis for the recommended dose limits for the lens of the eye for nuclear energy workers, as set by the International Commission on Radiological Protection (ICRP). The webinar presented expert opinions and perspectives behind the science.

Technical background

In order to prevent opacification (or clouding of the lens), which, in its advanced stages, is referred to as a cataract, dose limits have been defined for the lens of the eye. In April 2011, the ICRP issued a formal statement indicating that tissue reactions for the lens of the eye have dose thresholds that are, or might be, lower than previously considered. The ICRP therefore recommended a reduction in the equivalent dose limit for the lens of the eye to 20 mSv in a year, averaged over defined five-year periods (i.e., 100 mSv/5 years), with no single year exceeding 50 mSv. This recommendation is for nuclear energy workers; the ICRP did not change its recommended dose limit for the lens of the eye for members of the public.

In alignment with the ICRP’s recommendations, the CNSC discussion paper DIS-13-01, Proposals to Amend the Radiation Protection Regulations, proposed to:

  • change the equivalent dose limit for the lens of an eye for a nuclear energy worker from the current limit of 150 mSv to 50 mSv in a one-year dosimetry period
  • add a new dose limit of 100 mSv in a five-year dosimetry period (for the lens of an eye for a nuclear energy worker)

Speakers

Chris Clement, Scientific Secretary, International Commission on Radiological Protection

As ICRP Scientific Secretary, Chris Clement oversees the ICRP’s daily business, represents the ICRP in international fora, is Editor-in-Chief of the Annals of the ICRP, and has presented over 150 invited lectures in more than 25 countries. He has 30 years of experience in environmental remediation radiological counter-terrorism, and was previously director of radiation protection at the Canadian Nuclear Safety Commission. He has also been a member of the IRPA Executive Council since 2012.

Abstract: In 2012, the International Commission on Radiological Protection issued ICRP Publication 118, which provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. This presentation describes the ICRP’s process and rationale for developing the new recommendation, and some of its implications.

View the presentation (PDF)


Liz Ainsbury, PhD, Cytogenetics Group Leader, Public Health England Centre for Radiation, Chemical and Environmental Hazards

Dr. Liz Ainsbury is a Principal Radiation Protection Scientist from the UK's Public Health England Centre for Radiation, Chemical and Environmental Hazards. She has a number of publications on the basis for and operational aspects of the new European Basic Safety Standards, which fully implement the ICRP's recommendations, and is also leading an EU-funded project examining how low doses of ionizing radiation might contribute to cataract development.

Abstract: The following will be discussed and elaborated on in this presentation: the mechanisms involved in the formation of low-dose radiation cataracts, the impact of dose and dose rate, and the interplay among radiation, genetic background and age-related cataracts.

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Roy Shore, PhD, New York University School of Medicine (Professor Emeritus), and Chief of Research, Radiation Effects Research Foundation, Hiroshima, Japan (retired)

Dr. Shore served on the ICRP’s Committee 1 (Radiation Effects) for 16 years. He has also served on various committees or task groups for UNSCEAR, the World Health Organization, the U.S. National Council on Radiation Protection and Measurements, and the U.S. National Academy of Sciences. He was an investigator on the radiation cataract studies of the Japanese atomic bomb survivors and the Chernobyl clean-up workers.

Abstract: A summary of epidemiologic information on the dose rate effectiveness factor (DREF) for radiation cataracts will be presented, based on several new studies since the ICRP issued its revised recommendation on dose limits to the lens of the eye.

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Norman J. Kleiman, PhD, Columbia University, Mailman School of Public Health, Dept. Environmental Health Sciences, Director of Eye Radiation and Environmental Research Laboratory, Director of MS Degree Program in Radiological Sciences

Dr. Kleiman’s primary research interests revolve around examination of the effects of environmental exposures on eye tissues, including a variety of radiation exposures. He has considerable expertise in measuring radiation damage to the lens in both human subjects and experimental animal models. He has served on committees of the ICRP and NCRP, tasked with providing guidelines for ocular exposure limits, and has published extensively on radiation cataract risk for interventional cardiology medical personnel.

Abstract: The presentation will summarize the effects of ionizing radiation exposure on the eye, types and presentation of lens damage, methods to assess radiation-induced lens changes, and the generally underappreciated potential visual risks associated with cataract surgery in relatively young individuals still in the workforce.

View the presentation (PDF)

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