両眼同時発症した網膜中心動脈閉塞症の1例

A case of simultaneous and bilateral central retinal artery occlusion

要約　目的：新規経口抗凝固薬（NOAC）使用中に両眼同時発症した網膜中心動脈閉塞症（CRAO）の症例の報告。

症例：67歳，男性。主訴は両眼視力低下。既往歴に心房細動があり，NOACを内服中であった。

所見と経過：視力は右光覚弁，左指数弁。両眼に網膜中心動脈閉塞症を認めた。頭部MRIで新鮮な多発微小梗塞を認め，心房細動により生じた血栓が原因と考えた。NOACは全身塞栓症予防効果に優れ，固定量投与の利便性から，近年ワルファリンに代わり使用されることが多いが，ワルファリンと異なり薬効を判定するモニター方法が存在しない。本症例ではNOACの用量不足や服薬遵守不良で薬効が減弱していた可能性が考えられた。

結論：NOAC服用下でも両眼CRAOを発症することがあり，NOACの特徴や注意点を理解する必要がある。

Abstract　Purpose：To report a case of simultaneous and bilateral central retinal artery occlusion.

Case：A 67-year-old male was referred to us under the diagnosis of bilateral central retinal artery occlusion. He had noted blurring in the right eye at 11：30 a.m. and in the left eye at 1 p.m. the same day. He had been diagnosed with peroral rivaroxaban which was switched to edoxaban one month before. Rivaroxaban and edoxaban are claimed to be anticoagulants.

Findings and Clinical Course：Visual acuity was light perception right and counting left. Both fundus showed typical findings of CENTRAL retinal artery occlusion. Magnetic resonance imaging（MRI）showed numerous sites of microinfarction in the brain that appeared to be secondary to cardioembolic stroke due to atrial fibrillation. Visual acuity failed to improve and remained hand motion right and 0.09 left two months later.

Conclusion：This case illustrates that novel oral anticoagulants may not prevent central retinal artery occlusion as complication of artial fibrillation.