目的：评价经上皮准分子激光角膜切削术(Trans-PRK)联合0.02%丝裂霉素C(MMC)对中度近视患者角膜光密度的影响。

方法：回顾性病例分析。选择我院2021-01/06行Trans-PRK手术治疗的中度近视患者28例56眼，MMC组28眼术中联合使用0.02%MMC 20s； 对照组28眼术中未使用MMC。于术前，术后14d，1、3mo分别使用Pentacam眼前节分析仪测量不同直径范围及不同厚度分层范围内角膜光密度值。

结果：MMC组总角膜光密度值术前为16.60(15.70，17.10)，术后14d为16.63(15.90，17.50)、术后1mo为16.57(15.10，16.70)，术后3mo为16.04(14.60，16.60)； 对照组总角膜光密度值术前为16.30(15.50，17.30)，术后14d为16.20(15.20，17.10)、术后1mo为16.08(14.90，16.40)、术后3mo为15.60(14.60，16.40)。两组患者手术前后以角膜顶点为中心0～2mm直径范围术后14d角膜光密度值较术前升高(P<0.001)，在直径2～6mm内术后1、3mo角膜光密度值较术前升高(P<0.001)，在直径6～10mm内角膜光密度术后14d，1、3mo角膜光密度值较术前升高(P<0.01)； 两组患者角膜前120μm厚度角膜光密度值术后1、3mo角膜光密度值较术前降低(P<0.01)， 在中部厚度术后1mo角膜光密度值较术前降低(P<0.01)。

结论：术中使用0.02% MMC可在术后早期一定程度上降低角膜光密度值，增加角膜通光性。术后不同时间段观察不同范围内角膜光密度值变化可有效量化haze的发生和转归。

METHODS: Retrospective case analysis. Selected 28 patients with 56 eyes in moderate myopia who underwent Trans-PRK surgery from January 2021 to June 2021 in our hospital. They were divided into MMC group in 28 eyes with a combination of 0.02% MMC 20s during the surgery and the control group in 28 eyes was not use MMC during the surgery. The Pentacam anterior segment analyzer was used to measured the corneal density in different diameter ranges and different thickness layers before and after surgery at 14d, and after surgery at 1 and 3mo.

RESULTS: The total corneal density value of MMC group was 16.60(15.70,17.10 )before the surgery, after the surgery at 14d was 16.63(15.90,17.50 ), at 1mo was 16.57(15.10,16.70 ), at 3mo was 16.04(14.60,16.60 ). The total corneal density value of control group was 16.30(15.50,17.30 )before the surgery, after the surgery at 14d was 16.20(15.20,17.10 ), at 1mo was 16.08(14.90,16.40 )and at 3mo was 15.60(14.60,16.40 ). In the zone of 0-2mm diameter was centered on the corneal vertex, the corneal density of the two groups at 14d after the surgery was higher than those before surgery(P<0.001 ). In the zone of 2-6mm diameter, the corneal density of the two groups at 1mo and 3mo after surgery was higher than those before the surgery(P<0.001). In the zone of 6-10mm, the corneal density of the two groups at 14d, 1 and 3mo after surgery was higher than those before the surgery(P<0.001). In the layer of anterior 120 μm, the corneal density of the two groups at 1mo and 3mo after the surgery was decreased than that before surgery(P<0.01). In the middle layer, the corneal density of the two groups at 1mo after the surgery was decreased than those before surgery(P<0.01).

CONCLUSION:The use of 0.02% MMC during the operation can reduce the corneal density and increase the corneal light transmittance in the early postoperative period. The occurrence and prognosis of haze can be effectively quantified by observing the changes of corneal optical density in different ranges in different time periods after operation.