目的：研究角膜胶原交联术治疗圆锥角膜的疗效和安全性。

方法：对2015-04/2018-08在泰国朱拉隆功国王纪念医院行角膜胶原交联术的圆锥角膜患者病历进行回顾性分析。评估术前和术后1a的视力、屈光度、角膜地形图、高阶像差(HOA)、地形图参数和角膜密度。根据患者年龄是否小于24和30岁、基线角膜最大曲率(Kmax)是否小于55 D、基线最佳矫正视力(BCVA)是否小于0.3 LogMAR分组评估年龄、基线Kmax和BCVA对手术疗效的影响。分析术前Kmax、Kmean、平均等效球镜度数(MRSE)、视力、角膜最薄点厚度值、Kmax的变化以及相关参数的变化与角膜密度测量值变化之间的关系。P<0.05具有统计学意义。

结果：共155例患者185眼纳入研究，其中119例男性，36例女性。根据Amsler-Krumeich进行分类，1期和2期占优势(分别为37.84%和35.14%)。术后1a，平均裸眼视力(UCVA)提高0.1 LogMAR(P<0.05)。与基线BCVA较好组(术前BCVA<0.3 LogMAR)相比，基线BCVA较差组(术前BCVA≥0.3 LogMAR)术后BCVA改善大于0.2 LogMAR的眼数较多(78.26% vs 21.74%，P<0.05)。平均Kmax比基线下降2.36 D(P<0.05)。术前Kmax≥55 D的患眼术后Kmax下降超过2.0 D的眼数占比73%。距角膜顶点6 mm处角膜HOA下降0.40(P<0.05)。术后1mo～1a，0～6 mm区角膜密度测量值持续增加。术后1a，角膜密度的增加与最薄点厚度的减少呈线性相关。表面变异指数、高度非对称性指数、圆锥角膜指数、高度轴偏心指数在术后1a时下降(P<0.05)。术后1a，手术成功率为90.24%。术后1wk、1、3、6mo、1a角膜混浊发生率分别为11.35%、30.27%、15.67%、10.27%、2.16%。无角膜水肿发生，但有1例无菌性角膜炎患者。

结论：角膜胶原交联术可有效治疗圆锥角膜，使角膜变平、重塑，提高视力、HOA和角膜形态指数，晚期圆锥角膜Kmax也明显降低。

METHODS: Medical records of keratoconic corneas underwent accelerated collagen cross-linking at King Chulalongkorn Memorial Hospital, Thailand between April 2015 and August 2018 were reviewed. Preoperative and postoperative data at 1a of visual acuity, auto-refraction, corneal topography, higher-order aberrations(HOA), topometric indices and corneal densitometry were evaluated. Age of 24 and 30 years old, maximum keratometry value(Kmax)of 55 D, and baseline best corrected visual acuity(BCVA)of 20/40(or 0.3 in LogMAR unit)were used as cut-off values to highlight the cross-linking effects. The effect of age, preoperative Kmax and BCVA were analyzed. The association between the change of corneal densitometry and other factors including preoperative Kmax, Kmean, manifest refraction spherical equivalent(MRSE), visual acuity, thinnest pachymetry, the change in Kmax, and the change of those parameters were also analyzed. P<0.05 was considered statistically significant.

RESULTS: One hundred and fifty-five patients(185 eyes)were included. One hundred and nineteen patients were male and thirty-six patients were female. According to Amsler-Krumeich classification, stages 1 and 2 were dominant(37.84% and 35.14% respectively). At 1a, mean LogMAR uncorrected visual acuity(UCVA)improved by 0.1(P<0.05). The number of eyes of which postoperative BCVA improved more than 0.2 LogMAR was higher in the worse baseline BCVA group(preoperative BCVA ≥0.3)compared to the better baseline BCVA group(preoperative BCVA < 0.3)(78.26% vs 21.74%, P<0.05). Mean Kmax decreased from baseline by 2.36 diopters(D)(P<0.05). Seventy-three percent of the eyes of which Kmax reduced more than 2.0 D had preoperative Kmax ≥55 D. Corneal HOA at 6 mm from corneal apex decreased by 0.40(P<0.05). Corneal densitometry at 0-6 mm zone increased at 1mo and persisted 1a postoperatively(P<0.05). The relationship of the increase in densitometric value and the decrease of thinnest pachymetry at 1a were in linear fashion. Index of surface variance, index of vertical asymmetry, keratoconus index, index of height decentration decreased at 1a(P<0.05). Success rate at 1a was 90.24%. Postoperative corneal haze was found 11.35%, 30.27%, 15.67%, 10.27% and 2.16% at 1wk, 1, 3, 6mo and 1a respectively. No eyes developed corneal edema. There was one case of sterile keratitis.

CONCLUSION: Accelerated collagen cross-linking in keratoconus was effective to flatten, reshape the cornea, improved visual acuity, HOA and topometric indices. Great Kmax reduction was found in advanced keratoconus. The magnitude of Kmax reduction is also greatest among previous reports.