operation from this vantage where 13 mr per hour illuminated his face. Photos of the machine showed the door clearly as 22 inches wide, 28 inches high and 46 inches off the floor. Normally, this door was padlocked and was opened only to make adjustments. The record does not show that claimant ever gazed directly into the “open”’ Cesium source. Claimant wore a ring badge on his left hand and a badge onhisleft breast pocket, (estimated to be about 44 to 48 inches above his shoe soles), The window was large enough to admit his head, right arm and shoulder. The badge on his left breast pocket was well within the rectangylar area itluminated by the Cesium source each time he stood in front of the open door to open or close it, and received radiation while he was making the adjustments. Tests around the outside of the machine showed radiation from negligible to 13 mr per hour with the source “open” and the 22 x 28 door closed. A further test was run with the source on a wooden pallet with the yoke and supporting table removed entirely. The highest radiation measured in this test was 14.4 mr per hour at a point very near the cylinder wall, with the cylinder in “closed”attitude. The complete film badge record was on file for claimant. His accumulated total was .035 or (35 mr) for the period of about 8% months he worked around the machine. No prior significant exposure or work with radiation was claimed or supported. Records showed that monitoring and ‘“‘wipe” tests were made regularly to check to see if the source was emitting any harmful rays and to measure the amount of any radiation in the area. Testimony of the safety officer where claimant worked indicated that none of the readings showed any radiation that would be harmful to an individual. Claimant first noted blurred vision about May 1964 (about 22 monthsafter starting adjustments on the machine). He also alleged skin lesions and soreness of the face and head during the period of exposure. Records indicated that on October 21, 1963, claimant had 20/20 vision in each eye. By November 10, 1964, vision in the right eye was 20/100. The B & L screening tests on October 5, 1965 and November 15, 1966 showed “0” (zero) visual efficiency in the right eye. Recorded vision in the right eye in March 1967 was 1/200. Dispensary notes of March 11, 1963 indicated a “tender, slightly raised circumscribed area on occipital area of scalp approximately 2 cm in size”. Patient had had symptoms for about five days. Diagnosis was “probable cyst”. The cataract was removed from the right eye on March 8, 1967. The employee also worked near a drum of DICDI. The drum was closed. There is no record of him receiving any quantity of this chemical in his eye and no reason to assume that he did so. A co-worker had his eyes examined and there were no cataracts. The Bureau’s Claim’s Examiner summarized the issue as follows: To summarize briefly, a worker at the highest point of radiation in the room under normal operation would receive 13 mr per hour or 520 mr during a 40 hour week if he stood in front of the window at point “o”, Claimant worked steadily for 3 or 4 weeks about the machineat various points during installation and thereafter on numerous occasions for short periods. 112 There was a potential danger of his being directly in the collimated beam path at eye level with the detector unit pushed aside and the source in the open attitude. This is an extremely unlikely occurrence due to the safety precautions observed. Nevertheless, had such been the case he would have received radiation at the rate of several hundred rem per hour. This raises the question of just how long his right eye must remain in a half inch beam of radiation to receive a cataractogenic dose of radiation, and just what effect scatter would have on his film badgeif such an event did occur. The likelihood that claimant held his head quite still while the beam struck his eye directly for an extended period of time is highly unlikely. These questionable points in this summary are raised for the comments of a qualified specialist as they require specialized judgments bearing on the merits of the claim. Medical Evidence: The case file was referred to a specialist in the field of opthalmology for a determination of whether the claimant's cataract was caused by radiation. In his opinion that claimant’s cataract was not related to factors of employmenthesaid: -.. It is agreed that a single dose of 500 r to 800 5 to the human eye will produce a cataract (1X2). The greater the dose, the shorter the latent period before a cataract develops that will impair vision. Duke-Elder (3) states that 600 r is the minimum required to produce a cataract, or 1500 r over a period of one month. Gammarays, with which we are concerned here, permeate the entire eye. In contrast, “soft” X-rays (6 to 12 kV) do not reach the lens in any significant dose. Fractionated irradiations show a definite cumulative effect upon the lens (4). Epilation (in rabbits) by fractionated irradiations occurs only after 4 to 8 times the cataractogenic dose, whereas a single radiation dose sufficient to cause epilation also caused cataract (5}. Correlation between epilation and cataract in animals serves as a parameter for application of this data to man (1). Assuming that a 50% increase in radiation dose is needed to cause permanent epilation of the eyelashes compared to that needed to epilate scalp hair in man, at least 750 t/air in a single dose would be required to epilate the eyelashes. This would cause a cataract in some humans. Over long period of time, however, 4 to 8 times this dose (3000 to 6000 r/air) in fractionated doses would be necessary to cause epilation—much more than necessary to produce a cataract since damage to the lens epithelium seems to be cumulative, regardless of the fractionation. With these higher doses, however, the latent period of cataract formation would be shorter, a few months, Permanent damage to comea and conjunctiva also occurs with dosages over about 750 1, extrapolating animal data (1). Clinically, radiation cataract is first noted at the posterior pole of the lens. There is a latent period varying from 6 to 72 months (6) (7). This lag is because the damaged lens epithelium takes several months to develop into lens fibers and to migrate to the posterior pole of the lens. 113 4 q i 4