os ‘RTL. lee a Hh . A ae - 4 ue oe FIGURE 8.—Special high density goggles are worn by observers on-site at the Nevada Test Site. Note man at right of center without goggles, but who has turned away from the direction of burst. This pro-' cedure is equally safe providing there is no reflecting surface directly in view. other man’s visual acuity followed a similar pattern starting at 20/400 in both eyes in the area of retinal damage and 20/60 in the adjacent areas. These recovered to 20/50 and 20/80 in a month, and at one year later to 20/40 on one eye and 20/60 in the other in the areas of primary retinal damage." Experimental rabbits were exposed under nighttime conditions to the high altitude shot on August 1, 1958—a detonation in the megaton range at an altitude of about 48 miles. Lesions with diameters of about 500 microns were observed out to 345 miles--the farthest distance at which rabbits were exposed. Evaluation Nuclear detonations in the yield range tested offer no serious hazards to the eye when they are at very high altitudes, say above 150 miles, or below the horizon at the instant of burst. Detonations in the lower atmosphere should not be viewed directly without the aid of special high density goggles (Fig- ure 8). Past precautionary procedures of closing highways and air lanes near the testing sites at the times of bursts have added to the safety in respect to potential eye damage. The procedures also were useful in preventing a driver or pilot being startled while in motion. 25