不完全型網膜中心動脈閉塞症発症6年後に網膜中心静脈閉塞症をきたした1例

A case of central retinal vein occlusion six years after ipsilateral incomplete central retinal artery occlusion

要約　目的：不完全型網膜中心動脈閉塞症発症6年後に網膜中心静脈閉塞症を発症した症例の報告。

症例：74歳，男性。当科で左眼の不完全型網膜中心動脈閉塞症と診断され，治療後の経過は良好であった。そのときの光干渉断層像では，栓子が存在した上耳側では菲薄化があり，脈絡膜血管も拡張していた。不完全型網膜中心動脈閉塞症発症6年後に左眼の視力低下を訴え，当科を受診した。矯正視力は0.1と低下していた。眼底検査では，網膜静脈の拡張，蛇行を認め，上耳側と下耳側で網膜出血の程度の差を認めた。以上の所見から，網膜中心静脈閉塞症を発症したと診断した。1か月後の光干渉断層像では黄斑浮腫を認めた。

結論：典型的な陳旧期の網膜中心動脈閉塞症は，網膜全体が菲薄化するので網膜循環障害を合併した報告はない。本症例は不完全型網膜中心動脈閉塞症であったので，網膜の菲薄化が軽度であったため網膜循環障害を発症した可能性が高い。

Abstract　Purpose：To report a case of central retinal vein occlusion that occurred 6 years after the onset of incomplete central retinal artery occlusion.

Case：A 74-year-old male who was diagnosed with incomplete central retinal artery occlusion in the left eye at our hospital. He was followed up in good condition after treatment. During the follow-up, thinning of the retina was seen by optical coherence tomography（OCT）in the upper temporal area where a plaque was present. Choroidal blood vessels were also dilated. Six years after the onset of incomplete central retinal artery occlusion, he visited us again complaining of vision loss in the same eye. The best corrected visual acuity was 0.1. Funduscopy showed dilation of tortuous retinal vein and there was a difference between the levels of the retinal hemorrhage in the upper and lower temporal areas. Based on these findings, we diagnosed with central retinal vein occlusion. OCT taken one month later revealed macular edema.

Conclusion：Typical chronical central retinal artery occlusion may develop thinning of the whole retina with retinal circulatory disorders in the chronic phase. Because this case was incomplete central retinal artery occlusion, the retinal thinning was mild. That may be reason for the retinal circulatory disorders later.