[Efficacy of mitomycin C 0.02% for prevention of haze after transepithelial photorefractive keratectomy for mild and moderate myopia].

Objective: To investigate the efficacy of mitomycin C (MMC) 0.02% for prevention of haze after transepithelial photorefractive keratectomy (Trans-PRK) for mild and moderate myopia. Methods: Retrospective cohort study. We reviewed medical records of 295 patients (588 eyes) who underwent Trans-PRK with or without use of MMC. There were 45 patients (90 eyes) in the mild myopia group (aged between 18 and 41 years; 37 males and 8 females; myopia diopter <3.00 D) and 250 patients (498 eyes) in the moderate myopia group (aged between 18 and 46 years; 168 males and 82 females; myopia diopter: 3.00 to 6.00 D). The two groups were divided into subgroups with MMC 0.02% and without MMC, respectively. The time of intraoperative application of MMC, if there was, was 15 s and 30 s in the mild myopia group and the moderate myopia group, respectively. The mean follow-up time was 6 months. Postoperative best corrected visual acuity (BCVA), spherical equivalent (SE) and haze were analyzed and compared using an independent Student t-test or Mann-Whitney U test between subgroups. Haze variables were compared using chi-square statistics. Results: Haze was quantified with Fantes from grade 0.5 to 4. In the mild myopia group, all haze grades were 0.5 within 3 months. The incidence of haze was 6.25% (2/32) in eyes treated with MMC and 8.62% (5/58) in eyes treated without MMC; there was no statistical significance (χ²=0.00, P>0.999). In the moderate myopia group, the incidence of haze was 9.19% (24/261) in eyes treated with MMC within 3 months; the grade was 0.5 in 91.67% (22/24) of eyes with haze and 1 in 8.33% (2/24). The incidence of haze was 29.53% (70/237) in eyes treated without MMC; the grade was 0.5 in 60.00% (42/70) of eyes with haze, 1 in 18.57% (13/70), and 2 in 5.71% (4/70) within 3 months, and 0.5 in 15.71% (11/70) after 3 months (χ²=12.36, P=0.002). In the mild myopia group, BCVA was 5.0(5.0, 5.1) versus 5.0(5.0, 5.1) in the subgroups with MMC and without MMC (Z=-0.34, P=0.733). In the moderate myopia group, BCVA was 5.0(5.0, 5.1) versus 5.0(5.0, 5.1) in the subgroups with and without MMC (Z=-2.05, P=0.040). In the mild myopia group, SE was (0.33±1.07) D versus (0.32±0.57) D in the subgroups with and without MMC (t=0.25, P=0.805). In the moderate myopia group, SE was (0.66±0.85) D versus (0.53±0.67) D in the subgroups with and without MMC (t=2.97, P=0.003). Conclusions: MMC 0.02% was effective in preventing haze after Trans-PRK in the treatment of moderate myopia. However, it was not effective in mild myopia.目的： 探讨中低度近视眼行经上皮准分子激光角膜切削术（Trans-PRK）中使用0.02%丝裂霉素C（MMC）预防术后角膜上皮下雾状混浊（haze）的临床效果。 方法： 回顾性队列研究。纳入行Trans-PRK的近视眼患者295例（588只眼），其中低度近视眼（近视度数<3.00 D）45例（90只眼），年龄（20.53±4.95）岁（18~41岁）；男性37例，女性8例；32只眼术中使用MMC浸润角膜基质床。中度近视眼（近视度数≥3.00 D）患者250例（498只眼），年龄（23.66±6.12）岁（18~46岁）；男性168例，女性82例；261只眼术中使用MMC。低度和中度近视眼患者术中MMC的作用时间分别为15和30 s。所有患者随访6个月，观察指标包括最佳矫正视力、等效球镜度数及haze情况。正态分布资料的比较用两独立样本t检验，非正态分布资料的比较采用Mann-Whitney U检验，术后haze的发生情况比较采用χ²检验。 结果： 按照Fantes分级，将0.5~4级均纳入标准进行haze评估。术中使用MMC的低度近视眼患者术后haze发生率为6.25%（2/32），未使用MMC者为8.62%（5/58），且均为0.5级haze，差异无统计学意义（χ²=0.00，P>0.999）。术中使用MMC的中度近视眼患者术后haze发生率为9.19%（24/261），均为3个月内发生，其中91.67%（22/24）haze为0.5级，8.33%（2/24）haze为1级，未使用MMC者术后haze发生率为29.53%（70/237），其中84.29%（59/70）haze为3个月内发生，60.00%（42/70）haze为0.5级，18.57%（13/70）haze为1级，5.71%（4/70）haze为2级，未发生2级以上haze；15.71%（11/70）haze在3个月之后发生且均为0.5级，差异有统计学意义（χ²=12.36，P=0.002）。术后6个月，术中使用和未使用MMC的低度近视眼患者最佳矫正视力分别为5.0（5.0, 5.1）和5.0（5.0, 5.1）（Z=-0.34， P=0.733），等效球镜度数分别为（0.33±1.07）和（0.32±0.57）D（t=0.25，P=0.805），差异均无统计学意义；术中使用和未使用MMC的中度近视眼患者最佳矫正视力分别为5.0（5.0, 5.1）和5.0（5.0, 5.1）（Z=-2.05，P=0.040），等效球镜度数分别为（0.66±0.85）和（0.53±0.67）D（t=2.97， P=0.003），差异均有统计学意义。 结论： Trans-PRK联合0.02%MMC可以显著降低中度近视眼行术后haze的发生率和严重程度，但对于低度近视眼无明显效果。.