瘙痒抑制で片眼に冷却遮閉を行った後に生じた感覚性外斜視の1例

A case of sensory exotropia following unilateral occlusion with cooling to relieve eyelid itching

要約　目的：瘙痒抑制で片眼に冷却遮閉を行った後に感覚性外斜視を生じた症例の報告。

症例：8歳女児が，右眼瞼の瘙痒感が強くなり，皮膚科を受診し，抗アレルギー内服薬を処方され，濡らしたタオルで冷やすように指示された。その後，たまに複視を自覚するようになった。18日後，右眼の外斜を訴え受診した。視力は両眼とも1.5であったが，右眼は固視不良であり，左眼固視で，遠見45Δ外斜視18Δ右上斜視，近見50Δ外斜視18Δ右上斜視がみられた。両眼視機能も低下し，右眼を冷やし続けないことと左眼の時間遮閉を指示し，両眼視機能訓練を行った。4か月後に外斜視は消失し，両眼視機能も改善した。

結論：小児では，瞼をタオルなどで冷やす際にも，片眼のみで継続させると固視不良となり，感覚性外斜視になる可能性があり，注意が必要と思われた。

Abstract　Purpose：To report a case of sensory exotropia due to poor fixation following unilateral occlusion with cooling to relieve eyelid itching.

Case：An 8-year-old girl presented with exsodeviation of the right eye. She had had severe itching of the right eyelid 18 days before. She was prescribed anti-allergic drug and was instructed to cool the right eye with a wet towel by a dermatologist. She began to notice intermittent diplopia thereafter.

Cases and Findings：Visual acuity was 1.5 in either eye. The right eye showed poor fixation. The right eye showed, during primary fixation of the left eye, 45 prism diopters（Δ）exotropia（XT）for distance, 50Δ XT for near, and upward deviation by 18Δ. The binocular vision was absent. She was instructed to discontinue cooling the eye, and was treated with orthoptic training and part-time occlusion of the left eye. The eye position and binocular vision became normal after 4 months.

Conclusion：This case illustrates that prolonged occlusion with cooling of one eye may induce sensory exotropia in children.