Department of Ophthalmology and Vision Sciences, Federal University of São Paulo, São Paulo, Brazil
Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Br J Ophthalmol. 2019 Jan;103(1):137-142. doi: 10.1136/bjophthalmol-2017-310840. Epub 2018 Apr 2.
To evaluate the safety and efficacy of corneal cross-linking (CXL) followed by photorefractive keratectomy (PRK) for refractive correction in patients with bilateral asymmetric topography.
Forty-four patients (88 eyes) were enrolled in this prospective randomised clinical trial. CXL with subsequent PRK after 6 months was performed in one eye (study group), and PRK alone was performed in contralateral eyes (control group). Patients were followed for 24 months after PRK. Outcome measures investigated included visual acuity (VA), refraction, aberrometry, topography, pachymetry and endothelial cell count. Groups were compared with linear mixed regression and repeated measures logistic regression. Multiple comparison adjustment with the Holm procedure was performed.
At baseline, the logMAR VA (best spectacle corrected) in study and control groups was 0.12±0.13 (mean±SD) and 0.08D±0.14, respectively, and axial inferior-superior index (IS) (topographic IS) in study and control groups were 0.59D±0.31D and 0.58D±0.32D, respectively. After 24 months, a mean under correction of -0.50D was observed in both groups. Change from baseline in logMAR VA in study and control groups was 0.00D±0.08D and -0.02D±0.10D, respectively. Frequency of haze at 30 months in study and control group eyes was, respectively, 18.2% and 4.6% (p=0.05). There was no statistical difference between groups in spherical aberration and coma after adjustment for multiple comparisons.
Non-simultaneous CXL followed by PRK may be performed safely, and refractive results over a 2-year follow-up are highly similar in virgin and previously cross-linked corneas. Despite using mitomycin C, corneal haze can be significantly higher in the first year after PRK in eyes pretreated with CXL.
评估角膜交联（CXL）联合光折射性角膜切削术（PRK）治疗双侧非对称角膜地形图患者的安全性和有效性。
本前瞻性随机临床试验纳入了 44 名患者（88 只眼）。一只眼行 CXL 联合 6 个月后的 PRK（研究组），对侧眼行单纯 PRK（对照组）。PRK 后随访 24 个月。观察指标包括视力（VA）、屈光度、像差、角膜地形图、角膜厚度和内皮细胞计数。采用线性混合回归和重复测量逻辑回归比较两组间的差异，并用 Holm 程序进行多重比较调整。
基线时，研究组和对照组的 logMAR VA（最佳矫正视力）分别为 0.12±0.13（平均值±标准差）和 0.08D±0.14，研究组和对照组的轴向下-上指数（角膜地形图下-上指数）分别为 0.59D±0.31D 和 0.58D±0.32D。24 个月后，两组均出现平均欠矫-0.50D。研究组和对照组的 logMAR VA 自基线变化分别为 0.00D±0.08D 和-0.02D±0.10D。研究组和对照组在 30 个月时的角膜混浊发生率分别为 18.2%和 4.6%（p=0.05）。调整多重比较后，两组间球差和彗差无统计学差异。
非同期 CXL 联合 PRK 治疗可安全进行，在 2 年随访期内，未经交联和已交联角膜的屈光结果高度相似。尽管使用了丝裂霉素 C，但 CXL 预处理后行 PRK 的眼在术后 1 年内角膜混浊发生率明显更高。
