pigmentation persisted for several yearn before it haally disappeared. These pigmented streaks are notte be confused with conjunctival and corneal pigmentation of genetic origin noted in some of these people, which is in the superticial epiheiiun and is permanent Pten gia and pingueculite, During the early surveys the incidence of ptervaia and pingucculae was thought ta be greater i the exposed Rongelap people than inthe unexpesed comparison popula. tion. Hlawever, as the later group hos increase, this ne loguer appear to be the caw (ace Fable 14). Opactties uf the dens. Op aeitios at ihe lens have been a comin tindiog athe Miarstistlose (sce Table Db. They are scored tn order of decreasing Size as Cataracts (arbitrarily considered as a lens opacity dnpairing visual acuity bs > 20040), lens opacities, polychromatic shecte. and fecks. Special ticruscuple examinations for lens Hecks were made in 100, '4 trradiation of the lens in sullicient dosages may result ina spectrum of opacities ranging from polychromatic sheens to ftull-blow a cataracts, bess Only tn the early stages of cataract formation ean changes characterbue of radiation generally be recognized; more mture Cataracts due toradios Hon usually canner be ditherentioted fron these due to aging or disease. The development of bens opacities due te radiation depends on the charaeteristics of the radiation, the age of the individual al caposure, and the unterval after irradiauon, Neutrons are known to be several uimes as cataractogenic as ganinaoar bela rays and plaved an inportint role in cataract development in the Japanese exposed to the atone bombs and abe in evclotron workers!" Tn the Murshallese only ganas radiation need be considered because hu peutrons were javalved in the Cadlout wad the beta radiation dad not have sulficient energy te ine part a savmificant dose to the leas, The gamma rachation bad a fairly cnergetic spectrum (100 tu 1200 keV). Vhe U7)-rad dose was delivered ata decreasing mite over the two days of exposure. The discrete opacities were at most only a few niicrots in size and voukl inne way tapaic vision. Phe number of flecks increased with age in all groups, but they developed more rapidly in adolescent te- niales.'4° \ higher score in females aged 1310 20 atexpesure may dive been related to the radiation, Vhe higher tncidence of tleeks in adulescent feMales was thought to be assaciitled with cher high estrogen levels, Other lens opacities observed in the exposed Marshallese didi net dit the descriptions of raclistion-iaducedd types and were simian to those seen la the anes posed population. Phe abscuce of racliation-induced cabinets is hot anes pectea, since the dose te the Miusastiaatlese wars dechow the mini Munn dase of s niveer gai cays needed. The lapee of 20 years is well bevond the usual luteni period and ioseeis uolikely thist any such lesiuns will dhewelop. ALL the cataracts seen have been of the senile or presenile ype and no juvenile cata- racts have been noted. Possible correkition with die betes is discussed in Section TL G. a. Uhe slivhily higher incidence of cataracts in the exposed Rouvelip people over the year may be rebated toa slight: preponderance of older peaple in the es. posed population. Polvehromatic sheens, vellowish or “beaten brass” to blue-green in color. were noted in wine Miuarshullose, beth exposed vind nones pesca. “Phese were not associated with any lenticular opacities characteristie of radiation exposure, F. GROWTH AND DEVELOPMENT STUDIES OF EXPOSED CHILDREN 1. Dota Taken Dining cach anedical survey of the Matshatlese people, svstematne pedtatoe cxaniinations lave been conducted on subjects ander the chraacloyicalage of 20 vears (sce Vable 14) with the UNCepe Hon of adolescent girls who were pregnant or whe had hack babies. Vhe studies cetpisted af’ a brictin rays is considered te be ~ 200 rads and the dane te produce progressive lesions, ~ 300 cads.!" The terval hustory, poutine pliveicil ¢Namainition, palpeiion of the thyroid: vlan. and: axsexsament af growth aud development, Vhe growth status of the children expend to larger dases the latent period mii be shorter, and with lower doses it may be 38 vears. The sraallest lens opacities observed with slit- examination. From 05} te 1938 the growth data consisted of ronting measurements of stature and TOE Cabtaractowerie diese all x FoWs OME Qcud ibe nas latent period averages about 2 tab years. With lamp microscopy were lens flecks, which are thought te be defects in single lens fibers. These Toatih fallout bas been followed reguba Iv since the: initial weight. Tn E999) rocatgenographic evaluation of *Vheexe tiabes were cba da De. J. Bateman, BNE