25 opia. Also notable was their lack of retinoblastomas, malignant melanomas of the choroid, and basal cell carcinomaofthe eyelids. Ocular pathology caused by herpes simplex or zoster viruses was not seen. No cases ofretinal detachment occurred except in two people as a sequela of ocular surgery. Corneal scars, macular degeneration, vitreous floaters, and other degenerative intraocular condi- tions were seen in about the numbers expected in any part of the world. No Toxocara infestation or otherintraocular parasites have been encountered, fireball was observed by a small numberof people on Rongelap,and, thoughits distance from them precluded thermal injury to the skin from longwave(visible and infrared) light, injury to the ret- ina must be considered. The fireball was described by the Rongelap people as appearing “like the sun rising in the west.” They probably did not ” see it at its greatest luminescence, when the dam- aging oculareffects occur, because this comes a fraction of a microsecond after detonation, so that at a distance of 100 miles the fireball would not yet have risen above the horizon. Also, at that dis- and no ocular involvement by the parasites Onchocerca or filaria has been seen. In the one case of inactive leprosy on Rongelap noocular lesions have been noted. Some people have residual scars tancethe size of the image on the retina would be small. These factors probably explain why no one complained of blindness from seeing the fireball ing the 20-year period. Mostof the congenital malformations andfamilial ocular diseases found in Americans were not seen in the Marshallese, such as ocular dystro- fonizing radiation. The fallout on Rongelapresulted in a gammadose of 175 rads to the whole of yaws, but no active lesions have been seen dur- phias,retinitis pigmentosa (congenital nightblindness), congenital cataracts or glaucoma in the youngor familial glaucomain older people, and coloboma of theiris or posterior segmentof the and no retinal scars have been found in any of the people. body includingthe eyes. Beta rays from fallout deposited on the ground and contaminating the eyes resulted in some superficial exposure of the lids, conjunctiva, and cornea, but their low pene- apparently peculiar to this race were noted. The averagesize of the corneas is greater than in the U.S., more than 60% of the people examined hav- tration makes it unlikely that the lens or retina received anysignificant dose from this source. During the two days before evacuation, many of the people complained of someitching and burning of the eyes with some lachrymation. These symptoms enon has sometimes been found associated with ‘portantpart. Internal absorption of radionuclides eye. On the other hand,certain congenital traits ing corneas >14 mm in diameter. In ~5% ofthe people the retinal vessels showed increased tortuosity (corkscrew-like) and dilatation. This phenomthe sickle ceil trait, but the latter has not been noted in the Marshallese. Dietetic and hygienic conditions in the Marshail Islands have improved over the 20 years of this study. In earlier years, poor night vision in children due to vitamin A deficiency was occa- sionally found, and molluscum contagiosum was seen more frequently; also lesions involving the skin of the eyelids, forehead, and face. It has been several years since night vision impairment or molluscum has been seen. 2. Possible Radiation Effects Both the detonation in March 1954 andtheresulting fallout gaverise to several types of radia- tion that might cause injury to the eyes. Longwave radtation. Direct observation with the naked eye of the fireball of an atomic bombdetonation is known to produce retinal damage with scarring and possible blindness.33.34 The Bravo I00b122 may have beenrelated to radiation from fallout in the eyes, but physical and chemical irritation by the caustic fallout dust may have played an im- probably did not contribute to the radiation dose to the eyes. Conjunctivitis. The burning and lachrymation disappeared bythe time the people were evacuated to Kwajalein Island. However, at the time of developmentof beta burns, about 2 weeks after exposure, two men developed conjunctivitis and in- . flammation ofthe eyelids which may have been dueto beta irradiation. These lesions healed within several days. Corneal pigmentation. Beginning at about 2 months post exposure, in some people a pigmentedline was notedin the cornea atthe limbus in the hori- zontal axis of the palpebral fissure, which appeared to be below the surface of the epithelium. It varied from 0.5 to 2 mm in length. This may have been dueto beta radiation and was possibly related to the bluish pigmentation noted in the nail beds. The latter disappeared whenthenail bed grew outseveral months later, but the corneal