線維柱帯切除術後の角膜不正乱視のフーリエ解析

Fourier analysis of corneal astigmatism after trabeculectomy

（D-8AM-7）　目的：線維柱帯切除術後の角膜不正乱視の解析。

　症例と方法：同一術者により初回の線維柱帯切除術を受けた40例40眼を対象とした。原発開放隅角緑内障20眼，落屑緑内障17眼，原発閉塞隅角緑内障3眼であり，有水晶体眼18眼，偽水晶体眼19眼，無水晶体眼3眼である。術後1年まで，角膜中央3mm領域の形状をTMS-1で検査し，屈折力をフーリエ解析して，球面度数，2次正乱視，1次非対称乱視高次不正乱視の各成分を算出した。

　結果：角膜の球面度数成分と2次正乱視成分は，観察期間を通じて変化しなかった。角膜不正乱視を示す1次非対称乱視成分は，術後有意に増加した後，術後12か月までに術前の値に回復した。高次不正乱視成分も一過性に増加した。

　結論：線維柱帯切除術後に，角膜不正乱視成分，特に1次非対照乱視成分は有意に増加し，術後12か月までに術前の値に回復する。

purpose : To quantitate and analyze the irregular corneal astigmatism after trabeculectomy.

Cases and Method : A total of 40 eyes of 40 patients underwent primary trabeculectomy by a single surgeon. The series comprised primary open-angle glaucoma 20 eyes, capsular glaucoma 17 eyes and primary closed-angle glaucoma 3 eyes. There were 18 phakic eyes, 19 pseudophakic eyes and 3 aphakic eyes. The topography within 3mm of central cornea was evaluated up to one year after surgery using TMS-1. The corneal refraction was decomposed into spheric and astigmatic components by Fourier analysis.

Findings : The mean spherical equivalent and regular astigmatic component remained stationary throughout the observa-tion period. The decentration component increased significantly after surgery and returned to the preoperative value by 12 months. The higher-order irregularity component showed a transient postoperative increase.

Conclusion : Irregular astigmatism, particularly decentration component, increased significantly after trabeculectomy and returned to the preoperative value by 12 months after surgery.