Cataracts among Chernobyl clean-up workers: implications regarding permissible eye exposures.
The eyes of a prospective cohort of 8,607 Chernobyl clean-up workers (liquidators) were assessed for cataract at 12 and 14 years after exposure. The prevalence of strictly age-related cataracts was low, as expected (only 3.9% had nuclear cataracts at either examination), since 90% of the cohort was younger than 55 years of age at first examination. However, posterior subcapsular or cortical cataracts characteristic of radiation exposure were present in 25% of the subjects. The data for Stage 1 cataracts, and specifically for posterior subcapsular cataracts, revealed a significant dose response. When various cataract end points were analyzed for dose thresholds, the confidence intervals all excluded values greater than 700 mGy. Linear-quadratic dose-response models yielded mostly linear associations, with weak evidence of upward curvature. The findings do not support the ICRP 60 risk guideline assumption of a 5-Gy threshold for "detectable opacities" from protracted exposures but rather point to a dose-effect threshold of under 1 Gy. Thus, given that cataract is the dose-limiting ocular pathology in current eye risk guidelines, revision of the allowable exposure of the human visual system to ionizing radiation should be considered.
Worgul
B V
BV
Eye Radiation and Environmental Research Laboratory, Columbia University, New York, New York 10032, USA.
Kundiyev
Y I
YI
Sergiyenko
N M
NM
Chumak
V V
VV
Vitte
P M
PM
Medvedovsky
C
C
Bakhanova
E V
EV
Junk
A K
AK
Kyrychenko
O Y
OY
Musijachenko
N V
NV
Shylo
S A
SA
Vitte
O P
OP
Xu
S
S
Xue
X
X
Shore
R E
RE
D000328:Adult; D002386:Cataract / Q000209:etiology*; D047852:Chernobyl Nuclear Accident; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D005131:Eye Injuries / Q000209:etiology*; D005260:Female; D006801:Humans; D007903:Lens Capsule, Crystalline / Q000528:radiation effects*; D007904:Lens Cortex, Crystalline / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D009688:Nuclear Reactors; D011839:Radiation, Ionizing; D012306:Risk