The lens of the eye is one of the body’s most radiosensitive tissues.  Lens opacity (cataracts), which may be radiation-induced or related to other factors such as age, smoking or obesity, can lead to vision impairment and even blindness. In order to prevent radiation-induced cataracts, nuclear and non-nuclear regulatory bodies worldwide set equivalent dose limits for the lens of the eye for occupational exposure in planned exposure situations.

In 2011, the International Commission on Radiological Protection (ICRP) made a substantial revision to the equivalent dose limit and reduced it from 150 mSv per year to a threshold of 20 mSv per year averaged over five years (i.e. 100 mSv/5 y, with no single year exceeding 50 mSv). The NEA Expert Group on the Dose limit for the Lens of the Eye (EGDLE) was established to facilitate an exchange of information among member countries in the practical implementation of these revised dose limits.

The group met on 19 February 2021 to discuss and review its ongoing work. The EGDLE is currently working on a report that summarises the practical experiences worldwide in implementing the ICRP’s recommended equivalent dose limit for the lens of the eye for occupational exposure. The report is based on a 2020 survey that collected information and views from nuclear and non‑nuclear regulatory bodies, technical support organisations (TSOs), and other stakeholders.

The forthcoming EGDLE report will give an overview of the legislative changes related to the dose limits and the challenges associated with the recording of doses in member countries, as well as details on the practicalities of the implementation of the new dose limits (e.g. dosimeter placement, use of correction factors, approved and available dosimeters and accreditation process). The report will provide recommendations based on the various approaches taken to address the substantial change made to the equivalent dose limit. It will also include a rich reference library with links to national guidelines and resources.

The status of the implementation of ICRP recommendations differs from one country to another. Some countries have already adopted the new limit by implementing the ICRP recommendation with no changes, while some countries have not, and some others plan to adopt new dose limits in a progressive manner by gradually moving to lower dose limits. However, despite these differences, regulators and stakeholders worldwide could benefit from exchanging with other countries that already implemented the ICRP recommendations to ensure that additional efforts are strategic and optimised. As such, the forthcoming EGDLE report will also outline opportunities for future work and international collaboration.

See also