丝裂霉素抑制PRK后haze形成及屈光回退的研究

目的评价在高度近视的PRK手术中预防性使用丝裂霉素（MMC）抑制术后角膜上皮下混浊（haze）和屈光回退的效果，以寻求更佳的屈光手术方式。方法将不宜接受LASIK手术的高度近视患者（－6．0～－10．0D）按协议随机分为研究组40例（80眼）和对照组38例（76眼），研究组患者在PRK手术中使用0．02％丝裂霉素，对照组患者采用常规的PRK手术，术后两组用药方案一样，评价术后角膜上皮下混浊（haze）、角膜上皮修复、屈光状态、裸眼视力，矫正视力、角膜内皮细胞改变等情况。结果研究组未出现一眼2级或2级以上haze，无一眼出现术后最佳矫正视力下降，术后达到最佳矫正视力所需屈光改变小于－0．5D有70眼；对照组有26眼出现2级或2级以上haze，有14眼出现术后矫正视力下降，术后达到最佳矫正视力所需屈光改变小于－0．5D有37眼。研究组与对照组的差异有显著性。使用丝裂霉素未见明显毒副作用。结论PRK手术中预防性使用0．02％丝裂霉素，对术后减少角膜雾状混浊，防止屈光回退，改善裸眼视力和最佳矫正视力，是安全有效的。

Intraoperative use of mitomycin c inhibites corneal haze formation after photorefractive keratectomy

Objective To evaluate the results of the intraoperative use of mitomycin to inhibit haze formation after excimer laser photorefractive keratectomy(PRK)for high myopia in eyes and search for a better approaches to perform excimer laser photorefractive keratectomy for myopia.Methods The inclusion criteria were a spherical equivalent correction between-6.00 and-10.00 diopters(D)and inadequate corneal thickness to allow a LASIK procedure with a residual stromal thickness of more than 250 um.The eyes were divided into 2 groups according to the randomization protocol.After PRK,the study group comprised 80 consecutive eyes were treated with a single intraoperative dose of mitomycin(0.2 mg/mL),applied topically with a soaked microsponge placed over the ablated area and maintained for 2 minutes,and then the entire corneal surface was irrigated with balance solution.The control group comprised 76 consecutive eyes did not receive this treatment.Refraction,uncorrected visual acuity(UCVA),best corrected visual acuity(BCVA),corneal endothelial cell counts,and slitlamp evidence of corneal opacity(haze)or other visible complications were evaluated.Results No toxic or side effects were observed postoperatively.No study group eye had a haze rate higher than 1 during the 1 year followup;26 eyes(34.2%)in the control group did.At 1 year,the between group difference in the refractive outcome was statistically significant,with 70 study group eyes(87.5%)and 37 control group eyes(48.4%)within-0.50 D of the attempted correction.No study group eye had a BCVA loss during the follow-up;14 control eyes had lost 1 to 3 lines at 1 year.Conclusions It is safe and effective that the prophylactic use of a diluted 0.02% mitomycin solution applied intraoperatively in a single dose after PRK produced lower haze rates,better UCVA and BCVA results,and more accurate refractive outcomes than those achieved in the control group.