PRK，LASEKおよびLASIKの再手術例の比較検討

Clinical review of retreatment after PRK,LASEK or LASIK for myopia

　屈折矯正手術を行い1年以上の経過が追跡できた180眼のうち，再屈折矯正手術を必要とした症例を検討した。再手術はPRK 55眼中6眼（11％），LASEK 26眼中1眼（4％），LASIK 99眼中18眼（18％）に行われた。再手術の時期の平均は，それぞれ10.8か月，7.0か月，5.0か月であった。PRKとLASIKでは当初矯正量が大きいこと，LASIKでは高年齢，PRKとLASEKではhazeが強いことが再手術の主原因であった。LASIKでは，術後早期のregressionが原因で，全例で術後1年以内に再手術を行った。PRKでは，術後6か月以降に徐々にregressionが生じ，半数では術後1年以降に再手術を行った。

　We reviewed 180 eyes that received photorefractive surgery and that could be followed up for one year or longer. Retreatment for residual refractive error was performed on 25 eyes（13.9％）. They comprised 6 out of 55 eyes after PRK（11％）,1 out of 26 eyes after LASEK（4％）,and 18 out of 99 eyes after LASIK（18％）. Retreatment was performed after an average of 10.8,7.0 and 5.0months respectively. Following features were identified as risk factors for retreatment：higher initial corrections in PRK and LASIK,advanced age in LASIK,and haze formation in PRK and LASEK. Cases after LASIK received retreatment within one year for early regression. Regression developed gradually later than 6months after PRK. One-half of cases received retreatment more than 1 year after initial PRK.