水晶体乳化吸引術を行った先天水晶体欠損症の1例

Phacoemulsification and aspiration in a case of congenital lens coloboma

　水晶体乳化吸引術（PEA）を行った先天水晶体欠損症の1例を報告した。症例は44歳の男性で，左眼の視力障害を起こした。初診時の矯正視力は右1.5，左0.6で，左眼の水晶体には後嚢下の混濁と6時の辺縁に楕円形の欠損があり，同部の毛様小帯は少なかった。左眼の先天水晶体欠損症，白内障と診断して経過をみていたが，5か月後に成熟白内障となり，矯正視力が0.01まで低下したため，左眼にPEA＋眼内レンズ挿入手術を行った。術中，前嚢切開線が一部赤道部に及び，硝子体の一部が水晶体欠損部から前房内へ脱出した。後嚢の破嚢はなかつたが，眼内レンズは嚢外に固定した。退院時の左矯正視力は0.9で経過は良好であった。先天水晶体欠損症に対し白内障手術を行う場合には，毛様小帯の異常を考慮し，毛様小帯への負担の少ない術式を選択する必要がある。

A 44-year-old male presented with blurring of vision in his left eye since one month before. The left eye showed posterior subcapsular opacity and coloboma at the 6 o'clock position. The zonules were less numerous in this area. The visual acuity was 0.6 in the affected eye. He was diagnosed as congenital coloboma and cataract. Five months later, the visual acuity deteriorated to 0.01 due to mature cataract. The left eye was treated by phacoemulsification and aspiration followed by intraocular lens implantation. During surgery, the capsular incision extended to the equator of the lens, resulting in anterior prolapse of the vitreous. The posterior capsule remained intact. The intraocular lens was fixed out of the bag. After surgery, the visual acuity improved to 0.9. This case illustrates that due precaution is necessary in selecting the surgical procedure for congenital lens coloboma because of the inherent weakness of the zonule.