Radiation exposure: Ocular effects
Advanced, Special Problems or Issues in Anesthesiology
Occupational exposure to radiation can have many consequences, the most common being lens opacities and cataracts. The latency period between irradiation and cataract formation is inversely proportional to dose, and can range from years to decades. Current research suggests the germinative dividing cells of the anterior lens epithelium are primarily affected by radiation, and these damaged cells then migrate to the posterior pole of the lens. Because each lens is an avascular structure, there are no mechanisms to remove these damaged cells, which over time accumulate and create a symptomatic cataract. There is still much debate as to whether radiation-induced cataractogenesis requires a threshold exposure, or if they may form in response to damage to a single cell; however, there is good evidence to support that the latter may be true.
The most recent ICRP guidelines from 2011 reduced the occupational dose limit for lens equivalent dose to 20mSv/year averaged over 5-year periods, with no single dose exceeding 50mSv (previously, 150mSv/year was the recommended maximum).