A recent study published in Radiology by Dr Kazuo Neriishi and collaborators in October 2012 issue of Radiology gives important findings to indicate vision-impairing cataracts at radiation doses less than 1 Gy.
The IAEA cataract studies in recent years, through its project RELID (Retrospective Evaluation of Lens Injuries and Dose), among staff working in cardiac catheterization laboratories had shown increased prevalence of eye lens opacities. However, it was not clear if lens opacities will progress to visually disabling cataract.
The purpose of the recent study was to examine the incidence of clinically important cataracts in Atomic Bomb Survivors, 1986–2005, in relation to lens radiation doses between 0 and approximately 3 Gy to address risks at relatively low brief doses. Cataract surgery incidence was documented for atomic bomb survivors. Of 6066 survivors, 1028 underwent a first cataract surgery during 1986–2005. Their results indicate a radiation effect for vision-impairing cataracts at doses less than 1 Gy.
The evidence suggests that dose standards for protection of the eye from brief radiation exposures should be 0.5 Gy or less.
It may be mentioned that the ICRP had already issued a statement in April 2011 accepting 0.5 Gy as threshold dose to the lens of for eye.