角膜屈折手術を併用した人工水晶体移植術 特に角膜術後乱視におけるT cut法の検討

Simultaneous intraocular lens implantation and keratorefractive surgeries: Value of T-cut on corneal astigmatism

　160°四面切開5針前置結節縫合法（ECC-E＋PC-IOL）に角膜屈折手術（T cut法）を併用し，術後角膜乱視の変化から角膜加齢変性の角膜屈折手術に及ぼす影響について検討した．対象は80歳未満の76眼（平均年齢68.2歳）と80歳以上の39眼（平均年齢82.4歳）の115眼で，術後二主径線の経時的変化を測定した．

白内障手術に併用したT cut法は術眼の角膜外側輪部より2mm角膜中央寄りで，角膜縦軸と平行に5mmの角膜切開を加えた．角膜切開創の深さは角膜切開部位測定値の90％を目標とした．術後二主径線の変化は角膜平均乱視度（D）経過日数（月）1 2 3

対象者（76眼）1.8±0.8 1.1±0.5 0.5±0.3

高齢者（39眼）2.15±1.4 2.23±1.4 2.15±1.3

　であり，対象者（76眼）の角膜乱視は術後3カ月まで減少傾向にあったが，高齢者（39眼）の角膜乱視は術後1カ月以後にはほとんど変化が見られず，角膜の加齢変性は角膜屈折手術（T cut）の効果を著しく障害することがわかった．

We tried to minimize the postoperative corneal astigmatism after intraocular lens (IOL) implanta-tion by performing simultaneous corneal refractive surgery as T-cut method. We performed 160° 4 -plane incision, intracapsular cataract extraction, posterior chamber IOL implantation and 5-stitch interrupted sutures with 8-0 silk thread. The base of T cut was placed 2mm from the limbus and the radial cut paralleled the vertical corneal axis. The depth of incision was intended to be 90% of thecorneal thickness.

We treated a series of 115 eyes with the above procedure. Each case was evaluated as to the state of corneal curvature during the follow-up period. The series included 76 eyes aged 79 years or less and 39 eyes aged 80 or over.

The postoperative astigmatism showed signifi-cant tendency to decrease during the 3 months after surgery in the group under 79 years. This tendency was definitely absent in the more aged group, sug-gesting that the keratorefractive surgery is not beneficial in aged subjects of 80 years or over.

Rinsho Ganka (Jpn J Clin Ophthalmol) 42(4) : 387-390, 1988