急激な視力低下をきたした貧血による眼窩内血腫の1例

Acute visual loss in a case of orbital hematoma and anemia

　79歳女性に右眼の眼球突出と視力低下が突発し，ただちに受診した。右眼の矯正視力は0.01で，眼球運勤が全方向で制限されていた。貧血性網膜症を伴う重篤な鉄欠乏性貧血があった。画像診断で視神経を圧迫する眼窩内血腫があった。詳細な既往歴聴取で，発症1週間前に右前額部に軽い打撲があったことが判明した。血腫は2週間後に自然退縮し，矯正視力は0.8に回復した。本症例の診断と経過観察に，磁気共鳴画像検査（MRI）が有用であった。出血性素因がある場合には，本人が忘れている程度の小さな外傷を契機として眼窩内血腫が記こる可能性示す例である。

A 79-year-old female presented with sudden proptosis and visual loss in her right eye. Her corrected vis-ual acuity was 0.01. The ocular movement was restricted in all directions. She had severe iron deficiency anemia with anemic retinopathy. Diagnostic imaging showed orbital hematoma compressing the optic nerve. By repeated inter-views for past history, she had had a slight blunt trauma to the right forehead 1 week before onset. The orbital he-matoma underwent spontaneous regression 2 weeks later with the visual acuity improving to 0.8. Magnetic resonance imaging (MRI) was particularly useful in the diagnosis and follow-up of orbital hematoma. This case illustrates that orbital hematoma may be incurred by a slight injury when hemorrhagic tendency is present.