間欠性外斜視に対する内直筋plication術の術後屈折変化

Refractive change after medial rectus muscle plication in patients with intermittent exotropia

要約　目的：間欠性外斜視（IXT）に対する外直筋後転術および内直筋前転術は術後に近視化するとの報告がある。しかし，外直筋後転術および内直筋plication術の報告はない。そこで今回筆者らは，IXTに対する外直筋後転術および内直筋plication術の術後屈折変化について後ろ向きに検討した。

対象と方法：2016年2月〜2020年12月の間にIXTに対し片眼の外直筋後転術および内直筋plication術を施行し，術後1週，1か月，3か月時点での診察が可能であった47例47眼（男性27例・女性20例，平均年齢50.5±20.1歳）を対象とした。術前後の斜視角，等価球面度数（SE），乱視成分（power vector：J0，J45），平均角膜屈折力（mean K）を比較した。また，術前SEと術前後のSE変化量の相関（有水晶体眼のみ）と，plication量と術前後のSE変化量の相関を検討した。

結果：斜視角（近見/遠見）は術後有意に改善した（p＜0.001）。SE，J0，J45，mean Kは，術後3か月まで各観察時点で有意な変化はなかった。また，術前SEと術前後のSE変化量，plication量と術前後のSE変化量の間には各観察時点で相関はなかった。

結論：IXTに対する外直筋後転術および内直筋plication術は，有意な術後屈折変化はなかった。

Abstract　Purpose：It has been reported that the refraction is myopic after lateral rectus muscle recession and medial rectus muscle resection for intermittent exotropia（IXT）. However, there are no reports of lateral rectus muscle recession and medial rectus muscle plication. In this study, we investigated the postoperative refractive changes of lateral rectus muscle recession and medial rectus muscle plication for IXT retrospectively.

Subject and methods：Forty-seven patients（27 males and 20 females；age, 50.3±20.1 years）who underwent unilateral lateral rectus muscle recession and medial rectus muscle plication for IXT from February 2016 to December 2020 and could be examined at 1 week, 1 month, and 3 months after surgery were included in the study. The angle of deviation, spherical equivalent（SE）, astigmatism（power vector：J0, J45）, and mean keratometry（mean K）were compared before and after surgery. The correlation between preoperative SE and SE change in phakic eyes and the correlation between the amount of plication and SE change were also examined.

Results：The angle of deviation（near/distance）improved significantly after surgery（p＜0.001）, and SE, J0, J45, and mean K did not change significantly at each observation point until 3 months after the surgery. The correlation between preoperative SE and SE change in phakic eyes and that between the amount of plication and SE change were not correlated at each observation point.

Conclusion：Lateral rectus muscle recession and medial rectus muscle plication for IXT showed no significant postoperative refractive changes.