甲状腺機能異常のない甲状腺眼症の視神経症に対して早期の眼窩減圧術が奏功した1例

Orbital decompression was effective in a case of euthyroid Graves' optic neuropathy

　62歳女性に右眼視力低下が突発し，前部虚血性視神経症と診断された。その2か月後に眼窩に腫瘍性病変が発見され，当科を受診した。複視はなく，右眼は矯正視力0.2で，眼球突出と乳頭浮腫があった。磁気共鳴画像検査で外眼筋の肥厚があり，全身的に異常がなかったことから，甲状腺眼症類似の視神経症と診断した。初診から3か月後に眼窩外壁骨切除術を行った。得られた眼窩内容はBリンパ球細胞主体の脂肪組織であった。術後に乳頭浮腫は消失し，1.2の最終視力を得た。甲状腺機能に異常がない視神経症に対して眼窩減圧術が奏功した1例である。

A 62-year-old female had been diagnosed with anterior ischemic optic neuropathy following sudden visual loss in her right eye 2 months before. She was referred to us after detection of an orbital tumor with proptosis. Her corrected visual acuity was 0.2 right. Papilledema was present in the right eye. Magnetic resonance imaging showed hypertrophic extraocular muscles in the affected eye. Systemic findings were negative. We diagnosed her as euthyroid Grave's optic neuropathy. She underwent orbital decompression 3 months after her initial visit. The orbital content was mainly adipose tissue composed of B lymphocytes. Surgery was followed by disappearance of papilledema and improved visual acuity of 1.2. This case illustrates that orbital decompression surgery may be effective for euthyroid optic neuropathy.