Guidance on radiation dose limits for the lens of the eye: overview of the recommendations in NCRP Commentary No. 26

Abstract

Purpose: This review summarizes the conclusions and recommendations of the new National Council on Radiation Protection and Measurements (NCRP) Commentary No. 26 guidance on radiation dose limits for the lens of the eye. The NCRP addressed radiation protection principles in respect to the lens of the eye, discussed the current understanding of eye biology and lens effects, reviewed and evaluated epidemiology, and assessed exposed populations with the potential for significant radiation exposures to the lens while suggesting monitoring and protection practices.

Conclusions: Radiation-induced damage to the lens of the eye can include the loss of clarity resulting in opacification or clouding several years after exposure. The impact is highly dependent on the type of radiation, how the exposure of the lens was delivered, the genetic susceptibilities of the individual exposed, and the location of the opacity relative to the visual axis of the individual. The preponderance of epidemiological evidence suggests that lens damage could occur at lower doses than previously considered and the NCRP has determined that it is prudent to reduce the recommended annual lens of the eye occupational dose limit from an equivalent dose of 150 mSv to an absorbed dose of 50 mGy. Significant additional research is still needed in the following areas: comprehensive evaluation of the overall effects of ionizing radiation on the eye, dosimetry methodology and dose-sparing optimization techniques, additional high quality epidemiology studies, and a basic understanding of the mechanisms of cataract development.

Keywords:

• National Council on Radiation Protection and Measurements (NCRP)
• radiation-induced cataract
• radiation-dose limit for human lenticular opacification

Acknowledgements

This work was supported through funding to the National Council on Radiation Protection and Measurements by the Centers for Disease Control and Prevention and the U.S. Nuclear Regulatory Commission. We acknowledge the major support of the NCRP Secretariat, including President John D. Boice Jr, Managing Editor Cindy L. O’Brien, Office Manager Laura J. Atwell, and Executive Director David A. Smith. We express our gratitude to subject matter expert reviewers, Sophie Jacob, Wayne D. Newhauser, and Prem Subramanian.

Disclosure statement

The authors declare no personal conflicts of interest. The views expressed in this paper represent collective opinions of the authors, and are not necessarily those of their professional affiliations.