眼球運動制限が軽度な強度近視性斜視に対して横山法による手術を行った2例

Two cases of highly myopic strabismus with mild ocular motility disorders treated by the Yokoyama procedure

要約　目的：眼球運動制限が軽度な強度近視性内斜視に対して横山法による手術を行った2例の報告。

症例1：71歳，女性。視力は両眼とも（1.2）で，眼軸長は右29.24mm，左28.76mm。眼位は遠見40△内斜視（ET），近見で35△ETだった。明らかな眼球運動制限はなかった。横山法施行後の眼位は遠見正位，近見5△外斜位（XP）となった。Titmus Stereo Test（TST）は，Fly（＋），Animal（3/3），Circle（6/9）であった。

症例2：69歳，男性。視力は右（1.2），左（1.0）。眼軸長は右30.05mm，左30.52mm。眼位は遠見25△ ET，5△右上斜視（RHT）で，近見30△ ET，5△RHTだった。両眼とも軽度の外転運動制限があった。横山法施行後の眼位は遠見正位，近見4△XPとなった。TSTは，Fly（＋），Animal（3/3），Circle（8/9）であった。

結論：眼球運動制限が軽度である両眼性の強度近視性斜視に対して横山法が有用であると思われた。

Abstract　Purpose：To report 2 cases of highly myopic strabismus with mild ocular motility disorders treated by the Yokoyama procedure.

Cases：One patient was a 71-year-old woman. Her corrected visual acuity was 1.2 in both eyes and axial lengths were 29.24 mm in the right eye and 28.76 mm in the left eye. The preoperative ocular deviations at far and near vision were 40 prism diopters（△）of esotropia（ET）and 35△ET, respectively. She had no ocular movement limitations. After the Yokoyama procedure, the ocular deviations at far and near vision were orthophoria and 5△exophoria（XP）, respectively. Titmus Stereo Test（TST）showed Fly（＋）, Animal（3/3）, and Circle（6/9）postoperatively. The second patient was a 69-year-old man. His corrected visual acuity was 1.2 in the right eye and 1.0 in the left eye. His axial lengths were 30.05 mm in the right eye and 30.52 mm in the left eye. The preoperative ocular deviation was 25△ET with 5△ right hypertropia（RHT）at far vision and 30△ET with 5△RHT at near vision. Abduction was mildly limited in both eyes. After the Yokoyama procedure, deviation was orthophoria at far vision and 4△XP at near vision. TST showed Fly（＋）, Animal（3/3）, and Circle（8/9）postoperatively.

Conclusion：The Yokoyama procedure is effective for treating highly myopic strabismus with mild ocular movement dysfunction in the bilateral eyes.