Hafezi Farhad, Kling Sabine, Gilardoni Francesca, Hafezi Nikki, Hillen Mark, Abrishamchi Reyhaneh, Gomes Jose Alvaro P, Mazzotta Cosimo, Randleman J Bradley, Torres-Netto Emilio A
Laboratory for Ocular Cell Biology, Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland; Department of Ophthalmology, ELZA Institute, Dietikon, Switzerland; Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, California, USA; Faculty of Medicine, University of Geneva, Geneva, Switzerland; Department of Ophthalmology, University of Wenzhou, Wenzhou, China.
Department of Information Technology and Electrical Engineering, Swiss Federal Institute of Technology Zurich, Zürich, Switzerland.
Am J Ophthalmol. 2021 Apr;224:133-142. doi: 10.1016/j.ajo.2020.12.011. Epub 2021 Jan 30.
To determine whether corneal cross-linking (CXL) with individualized fluence ("sub400 protocol") is able to stop keratoconus (KC) progression in ultrathin corneas with 12-month follow-up.
Retrospective, interventional case series.
Thirty-nine eyes with progressive KC and corneal stromal thicknesses from 214 to 398 μm at the time of ultraviolet irradiation were enrolled. After epithelium removal, ultraviolet irradiation was performed at 3 mW/cm with irradiation times individually adapted to stromal thickness. Pre- and postoperative examinations included corrected distance visual acuity (CDVA), refraction, Scheimpflug, and anterior segment optical coherence tomography imaging up to 12 months after CXL. Outcome measures were arrest of KC progression at 12 months postoperatively and stromal demarcation line (DL) depth.
Thirty-five eyes (90%) showed tomographical stability at 12 months after surgery. No eyes showed signs of endothelial decompensation. A significant correlation was found between DL depth and irradiation time (r = +0.448, P = .004) but not between DL depth and change in K (r = -0.215, P = .189). On average, there was a significant change (P < .05) in thinnest stromal thickness (-14.5 ± 21.7 μm), K (-2.06 ± 3.66 D) and densitometry (+2.00 ± 2.07 GSU). No significant changes were found in CDVA (P = .611), sphere (P = .077), or cylinder (P = .915).
The "sub400" individualized fluence CXL protocol standardizes the treatment in ultrathin corneas and halted KC progression with a success rate of 90% at 12 months. The sub400 protocol allows for the treatment of corneas as thin as 214 μm of corneal stroma, markedly extending the treatment range. The DL depth did not predict treatment outcome. Hence, the depth is unlikely related to the extent of CXL-induced corneal stiffening but rather to the extent of CXL-induced microstructural changes and wound healing.
通过12个月的随访，确定个体化能量密度的角膜交联术（CXL）（“sub400方案”）能否阻止超薄角膜圆锥角膜（KC）的进展。
回顾性干预性病例系列研究。
纳入39只在紫外线照射时患有进行性KC且角膜基质厚度为214至398μm的眼睛。去除上皮后，以3mW/cm进行紫外线照射，照射时间根据基质厚度进行个体化调整。术前和术后检查包括矫正远视力（CDVA）、验光、眼前节分析系统检查以及CXL术后长达12个月的眼前节光学相干断层扫描成像。观察指标为术后12个月时KC进展的停止情况以及基质分界线（DL）深度。
35只眼（90%）在术后12个月时显示断层扫描稳定。没有眼睛出现内皮失代偿的迹象。发现DL深度与照射时间之间存在显著相关性（r = +0.448，P = .004），但DL深度与K值变化之间无显著相关性（r = -0.215，P = .189）。平均而言，最薄基质厚度（-14.5±21.7μm）、K值（-2.06±3.66 D）和密度测定值（+2.00±2.07 GSU）有显著变化（P < .05）。CDVA（P = .611）、球镜度数（P = .077）或柱镜度数（P = .915）无显著变化。
“sub400”个体化能量密度CXL方案使超薄角膜的治疗标准化，并在12个月时以90%的成功率阻止了KC的进展。sub400方案允许治疗角膜基质薄至214μm的角膜，显著扩大了治疗范围。DL深度不能预测治疗结果。因此，该深度不太可能与CXL诱导的角膜硬化程度相关，而更可能与CXL诱导的微观结构变化和伤口愈合程度相关。
