長期に眼内鉄片異物が存存したが網膜機能が良好であった眼鉄錆症の1例

A case of longstanding intraocular ferrous foreign body with intact retinal functions

　62歳男性が右眼の視力低下で受診した。37年前に鉄板を切断中に異物が右眼に当たった既往があった。前医で高眼圧に対する点眼を受けていた。右眼視力は0.01で，白内障，虹彩と隅角の色素増加があった。CTで毛様体扁平部に異物があり，摘出した。異物の周囲に被膜はなかった。異物の組成は95％以上が鉄であり，前房水に鉄イオンの増加と，虹彩に鉄成分の沈着があった。白内障手術後の視力は1.5で，眼底の色調は正常であり，網膜電図に異常はなかった。鉄性異物が被膜で覆われていなくても，長期間網膜機能が良好であり得ることを示す症例である。

A 62-year-old male was referred to us for impaired vision in his right eye. He had been hit by a foreign body in his right eye while cutting an iron plate 37 years before. He had been treated for elevated intraocular pressure by the referring physician. His visual acuity was 0.01 right. The affected eye showed cataract and increased pigmentation in the iris and chamber angle. Computed tomography showed a foreign body in the pars plana of the ciliary body. The surgically removed foreign body proved to be a ferrous piece with no surrounding membrane. There was a high content of iron ion in the aqueous. The resected iris tissue showed ferrous deposit. He regained visual acuity of 1.5 after cataract surgery with normal fundus findings and normal electroretinographic responses. This case illustrates that retinal functions may remain intact after longstanding intraocular noncapsulated ferrous material.