ABC | Volume 112, Nº4, April 2019

Original Article Barbosa et al Prevalence of lens opacity Arq Bras Cardiol. 2019; 112(4):392-399 Figure 5 – Frequency (%) of use of suspended radiation protection by interventionists (n = xx). 28 50 38 12 Non-users Regular users Irregular users (only when available) Eventual users radiology. The present study aims at filling this gap, providing nationwide information on the theme. Our findings showed that interventional cardiology professionals have significantly more lens changes than non‑exposed individuals (p = 0.0058), although the non‑exposed groups were significantly older. Sucapsular cataract was more frequent in the exposed group (p = 0.0081) than in controls, confirming previously published results. 18,21,23 The other types of cataract (cortical and nuclear), when separately analyzed, were not prevalent in the exposed group, corroborating results from previous studies. 23 On the other hand, the prevalence of subcapsular + cortical cataract was higher in the exposed than in control group. Our findings showed a higher prevalence of cataract in the left eye than in the right eye among participants. This was also reported in previous studies showing that, during interventional procedures, the left side of the brain receives higher doses of radiation, due to positioning of the professional during the tests. 25,26 Analysis by occupational category highlighted a higher prevalence of lens opacity, of any type, in the exposed group (38% of ICs) and in clinicians that were not exposed to radiation (15%). PSC cataract, a lens opacity related to radiation exposure, was found in 13% of ICs and in only 3% of clinicians. Elmaraezy et al., 27 in a metanalysis recently published, found a cataract prevalence, of any type, of 36% among ICs, similar to our results. In this same meta-analysis, all studies included reported a significant prevalence of subcapsular cataract in ICs, with no difference between the prevalence of cortical and nuclear opacity. In the French O'CLOC study (Occupational Cataracts and Lens Opacities in interventional Cardiology), Jacob et al. 21 found a prevalence of 17% of PSC in ICs and of 5% in the control group, similar to our findings. 21 It is worth pointing out that, in the O’CLOC study, the control group was composed of non-physicians, differently from our study, in which radiation‑exposed physicians were compared with medical cardiologists (non-interventionists), similar in number and age, but not exposed to ionizing radiation. Vañó et al. 18 found a significant prevalence of PSC cataract among interventional catheterization professionals – physicians, nurses and technicians. We did not find a significantly greater prevalence of cataract in radiation‑exposed non-physicians when compared with the control group. This can be mainly explained by the small number of non-physicians included in the study (25% nurses and 3% nursing assistants), professional categories and years of work in catheterization laboratory. Professional activity measured in years of work and number of procedures performed annually can be predictors of increased risk of damage, as we tend to associate them with increased cumulative dose. However, we should consider that the use of protective devices and the ability of professionals in performing the procedures may significantly change these cumulative doses. Some authors have shown that there is no clear relationship between the incidence of lens opacity and number of procedures, as in the study by Jacob et al. 21 in which the number of procedures varied from 50 to 1,267, with a mean of 542 ± 312 procedures per year. In their study, 21 the risk for cataract was lower in regular users of lead glasses as compared with irregular users, without statistical significance though. 21 In our study, only 40% of the radiation-exposed volunteers reported to wear lead glasses on a regular basis, which make our sample size (considering both exposed and non-exposed groups) even smaller. Besides, variables such as age, work experience, number of procedures performed, lead shielding, among others make it difficult to establish any association between the regular use of protective device and the findings. Also, there are no data regarding occupational dose. Studies have highlighted the importance of the accuracy of dosimetry measurements in clinical practice to determine correlations of radiation doses and effects. 28,29 In the present study, we could not estimate the radiation dose received by the participants exposed. Also, by interview of participants, we found that only 63.8% of them used personal radiation dosimeters over the lead (chest) aprons for their own control, although this device is the most reliable way to measure cumulative radiation over a month, and its usage is regulated by current radiation protection legislation. 30,31 Variations in individual doses recorded in dosimeters can help in the understanding of conditions associated with increased doses and establishment of safer conditions during the procedures. Safety promotion, by means of reduction of radiation doses delivered to the patient and the staff, is a responsibility of the operator. Fluoroscopy and cinefluorography time should be controlled, as well as the total cumulative dose for the patient (air kerma) should be monitored and registered at the end of the test, For dose reduction, adequate collimation and use of virtual collimation are essential, in addition to other factors, including virtual expansion and geometric adjustments may affect the 396