USE OF SUBJECTIVE AND NONSUBJECTIVE METHODOLOGIES TO EVALUATE LENS RADIATION-DAMAGE IN EXPOSED POPULATIONS - AN OVERVIEW

The general epidemiological acceptability of prevalence, or incidence, for assessing risk of radiation cataract development has dictated an almost exclusive dependence on cataract onset as a measure of cataract ogenicity for given doses of radiation. The advent of instrumentation capable of acquiring images amenable to quantitative analyses offers t he possibility of exploiting ''relative opacification'' as an added, i f not exclusive, parameter. This development is particularly important in efforts to assess populations such as that in the Altai, which are temporally far removed from their exposure and among whom there exist s a large subset with extant cataracts. The new technologies, Scheimpf lug and retroillumination imaging, combined with the application of th e appropriate analytical algorithms can not only provide quantitative and nonsubjective assessment of lens transparency, but also serve as a means to immortalize the state of the pathology at the time of acquis ition. Highly relevant to the assessment of an aging exposed populatio n is the use of lens epithelial fragments as potential dosimeters. The material is routinely available as a result of cataract extraction pr ocedures and is amenable to the application of a modified micronucleus (MN) assay. The MN assay in the lens has tremendous advantages over i ts use in other tissues for a number of reasons, not least of which is that lens MNs are extremely long-lived. Given the relative ease of ap plication and its potential as a radiation bioindicator, the lens MN a ssay should be considered in any follow-up of populations exposed to i onizing radiation.