Lens dose and risk of radiation-induced early lens opacities among hospital staff. A cross-sectional study

Abstract

The main health effect of exposure to ionizing radiation on the eyes is lens opacities and cataracts. Recent findings have raised questions about the pathogenesis of lenticular damage and the exact threshold dose for the onset of this effect. Occupational dose limits for the lens have been therefore recently reduced to 0.02 Gy/year averaged over 5 years with no single year exceeding 0.05 Gy/year. Healthcare workers can be exposed to ionizing radiation during interventional and other medical procedures. The aim of our study was to evaluate the annual dose to the lens in a large group of healthcare workers exposed to ionizing radiation who are working in a university hospital in Rome and to evaluate a dose-response relationship between lens exposure and the onset of lenticular opacities. We reviewed the exposure data of 702 subjects; the average annual dose to the crystalline lens was calculated using a physical algorithm. Moreover, the clinical records of 107 radiation exposed workers were reviewed: the presence of radiation-compatible opacities were assessed for all operators according to the Lens Opacities Classification System (LOCS) III and Merriam-Focht classification. Annual doses exceeding 0.02 Gy were found in 2.1% of the exposed population. Incipient lenticular opacities were observed in 18.6% of the study population. The presence of alterations was associated with higher lens dose (>0.0092 Gy). Based on our results, optimization of procedures and protection of the lens from ionizing radiation by means of personal protection equipment are strongly recommended in higher exposure scenarios.