Lenticular opacities in populations exposed to chronic low-dose-rate gammaradiation from radiocontaminated buildings in Taiwan

Epidemiological and experimental studies have revealed the cataractogenic p otential of large acute doses of radiation. However, studies on the dose-re sponse effect and the incidence of lenticular changes after exposure to chr onic low doses of radiation have seldom been conducted, To evaluate quantit atively the lenticular changes in a population exposed to chronic low-dose- rate gamma radiation in their daily living or school environment in steel b uildings contaminated with Co-60 in Taiwan, a total of 114 exposed individu als participated in a thorough ophthalmological examination in 1998, The le nticular opacities were evaluated by slit-lamp biomicroscopy after full pup il dilatation and were scored by the Lens Opacities Classification System I II (LOCS III) and a modified subclinical minor lenticular focal defects sys tem. These individuals were further divided into those less than 20 years o ld, those between 20 and 40 years old, and those more than 40 years old to evaluate the effects of age. The cumulative doses were assessed for each in dividual using the Taiwan Cumulative Dose (TCD) estimation system. A signif icant dose-dependent increase in the numbers of focal lens defects in those less than 20 years old was demonstrated, while less significant changes we re observed in the other two age groups or by the LOGS III scoring. Results suggested that chronic low-dose-rate irradiation might induce minor lentic ular changes, especially in lenses of young subjects. The delayed clinical changes in these young exposed subjects warrants further long-term followup . (C) 2001 by Radiation Research Society.