ey: we ag Wye > promptly as energy in the visible light region*because of the thin atmesphere.” Hrincipally for t:is reason,such high alti. : tude detonations du not present a serious hazard for eye dani- age. Detonations occurring at lesser altitudes encounter more “ atmosphere, where there are prealer opportunities fur iater- B action of the bomb debris with the air, resulting in a greater” : fraction of the total energy appearing as prompt visible light. Detonations below about 60 miles can produce sufficient' energy in the visible light region to be a potential eye hazard if they occur shove the horizon and ure viewed'directly. Ex-. perience at Hiroshima and Nagasaki suggest that perma- ~ nent eye injury would be expected only if one were looking : - directly at the fireball. This applies only to‘the instant of ° ~ burst. If the detonation occurs below the horizon, the natant : of high thermal energy release is past before the fireball rises into view. Under these conditions human reflexes of ® : blinking or turning away shuuld further jngure safety. “oee _ The Dete “3 RP a ' There have been no recorded permanent ‘eye injuries to pe J+ FIGUVE b.- Bpecial hichdennlty: ; persons off-site, although a few individuais near the Nevada, Test Site have complained of temporary eye impairment.| The burst from a 1.4 million tons detonation that took place *” Lite over Johnston Island in the Pacific on July 9,°1962 at an alti- “"Te. |, 7) geys tude of about 250 miles was viewed directly under nighttime ~#. i -eonditions by thousands in the Hawaiian Islands without any reported eye injury. : Six military personnel participating in nuclear weapons “= tests have received eye injury —only one of which resulted in ° a severe visual handicap.™ * The latter individual "sneaked" -. a view over his left shoulder at the time of the detonation resulting tn & reduction of 20/20 vision to 20/100 in his lefteye. 3 It did not improve with time, His right eye apparently was “S %:"" “worn hy observers ar-site ax ¢ Nevada Test Bite.Notegan gt right of center witheul goyeh but who has turned awgy from the direction of burst. This pi cedure is equally.safe -pfeyiding there i: no reflecting murfy directly in views: °F, a a - 1 a Je, . “tin the adjacent areas,";Theserecovered to 20/50 arfd 20/fv: 7 @ month, and at one year later to 20/40 un une eye and 2) in the other in the areas of primary retina! dumage.* Experimental rabbits were‘exposed under nighttime con > tions te the high altitude shot on August 1, li0d- a detunati ' At in the mewaton range at an siGtude of abou! th miles, Lesig shielded by his nose and retained its 20/20 visual acuity.” °°? °*! (Values such as 20/100 represent the ability of the eye to read 7* é te with diameters of about 600 microns were observed out standard letters and characters at 20 feet that anormal eye could read at 100 feet. 20/400 is generally interpreted as (~~: LO “€ Bvalvation . os Nuclear detenations in the yield range tested offer no seria legal blindness.) Two military personnel at Johnston Island participating in * : « ““ 4945 miles —the farthout distance at which ruliiits were expogs hazards to the eye when they are at very jib altitudes, @ * above 150 miles, or below the horizen at (he instant of bur « ttireetly without the ald of special high devicily gogieion (F the high altitude teats in 1962 also received eye injury, Im- # 3 ~ "+ Detonations in the lower atmosphere should not be view one man dropped to 20/400 for the area of primary retinal “* yre 4) Past precautionary procedures of cioniay highwa mediately after the exnosure, the visual acuity of hoth eyes of, injury and 20/100 for adjacent areas of the retina. This man's visual acuity recovered (o 20/30 in one eye and 20/40 in the other about une month later, and to 20/26 in both eyes about a year afterwards in the aren of primary retinal damage. The 24 f “# other man's visual acuity followeda almilur pattern starth €-" at 20/400 in both ecyea‘in the'ares of retina! damage and an "and air lanes near the testing sites ul the tices of bursts ha - added to the safety in reapect to potential ov<« dumupge. T procedures piso were weeful in prevention: oo driver or pi being startled while in motion.