黄斑下に迷入した眼内鉄片異物の1例

A case of intraocular foreign body located in the submacular space

　52歳男性が草刈り機を操作中に，右眼に異物が飛入した。受傷当日の所見として，右眼視力は光覚弁で，角膜中央部に穿孔創があった。前房出血と硝子体出血のために眼底は透見不能であった。画像診断で眼内異物が同定された。硝子体手術と水晶体摘出術を行い，細長い異物が耳側上方の網膜経由で黄斑下に迷入していた。網膜裂孔の縁が不整で，その周囲に網膜下血腫があるため，裂孔経由での異物摘出は行わなかった。異物が大きいので硝子体鑷子では保持できなかった。黄斑部網膜の二次的損傷を避けるため，耳側下方の網膜に意図的に作った裂孔を経由し，眼内マグネットで異物を摘出した。異物は5×1.5×2mmの鉄片であった。眼内異物で網膜下に異物が迷入しているとき，眼内マグネットの操作は慎重に行う必要がある。

　A 52-year-old male was hit by a foreign body in his right eye while operating a mowing machine. When seen the same day,his visual acuity was light perception right. A perforating wound was present in the central the cornea associated with heavy hyphema and vitreous hemorrhage. An intraocular foreign body was identified by diagnostic imaging. During vitrectomy,an oblong foreign body was found in the submacular space after perforating the superior temporal retina. We did not try to remove the foreign body through the retinal tear,as it had ragged margin and was surrounded by subretinal hematoma. Vitreous forceps could not be used because of the size of foreign body. It was removed by an intraocular magnet through an artificial retinal tear created inferior temporal to the macula. It was a piece of iron measuring 5×1.5×2mm. This case illustrates that intraocular foreign body may be located in the subretinal space. Intraocular magnet ought to be used under utmost precaution in such an instance.