被爆者の眼軸長

Axial length of atomic bomb survivors in Nagasaki

（P−339）　日赤長崎原爆病院眼科で過去4年間に白内障手術を受けた778名につき，被爆歴，眼軸長，屈折状態を病歴から検索した。すべて1945年以前の出生で，年齢は76.5±8.6歳であり，男性263名，女性515名であった。被爆歴は356名にあり，被爆歴のない422名は対照として扱った。白内障の型は，被爆者と対照群との間に差はなかった。強度近視は，被爆者11名（3.2％），対照群24名（6.0％）にあり，有意差はなかった（p＝0.083）。被爆時に18歳以下で被爆距離が2km以内のものは24名であり，強度近視者はいなかった。眼軸長は，男女間，および被爆者と対照群との間に有意差はなかった。被爆者であっても放射線の影響がないと推定されるものがあり，個々についての被爆線量が不明なので，今回の検索結果は必ずしも確定的ではない。

We reviewed a series of 778 patients who had cataract surgery during the past 4 years at the Nagasaki Atomic Bomb Memorial Hospital. We evaluated the history of exposure to radiation by atomic bomb in 1945, axial length and state of refraction. All were born before 1945. The series comprised 263 males and 515 females. Their ages averaged 76.5±8.6 years. History of exposure to radiation was present in 356 patients. The remaining 422 patients served as control. There was no difference in the type of cataract between the two groups. High myopia was present in 11 irradiated patients (3.2%) and in 24 patients in the control group (6.0%). The difference was not significant (p= 0.083). There was no high myopia among 24 patients who were aged 18 years or less at the time of radiation and who were within 2 km from the epicenter. No difference was present regarding the axial length between the two groups or between both sexes. The present result is not definitive because “irradiated group” would include those with little or no exposure and because precise data has not been available about the dosis of radiation.