J Refract Surg. 2022 Aug;38(8):511-519. doi: 10.3928/1081597X-20220713-01. Epub 2022 Aug 1.
To investigate the 36-month clinical outcomes of under-flap stromal bed CXL (ufCXL) and report on its ability to stabilize post-laser in situ keratomileusis (LASIK) ectasia.
This case series included 20 eyes with diagnosed early post-LASIK ectasia treated with ufCXL. Inclusion criteria were early, mild post-LASIK ectasia, defined as new-onset postoperative manifest refraction cylinder of 1.50 diopters (D) or less, with new topographic inferior steepening consistent with ectasia, uncorrected distance visual acuity of 20/40 or better, and corrected distance visual acuity of 20/25 or better. The existing LASIK flap was lifted, 0.25% isotonic riboflavin was applied directly to the stromal bed, the flap was repositioned, and 18 mW/cm ultraviolet light was applied for 5 minutes to the corneal flap surface. Post-ufCXL ophthalmic data were compared to pre-ufCXL baseline measurements.
Visual outcomes were maintained pre-ufCXL to 36 months post-ufCXL, with preserved safety index ( = .6545), efficacy index ( = .4980), spherical equivalent accuracy ( = .1536), defocus equivalent accuracy ( = .1032), central corneal thickness ( = .5196), and corneal irregularity indices at 3 mm ( = .8548) and 5 mm ( = .3399). Refractive astigmatism significantly decreased from 0.83 to 0.55 D pre-ufCXL to post-ufCXL ( = .0439), as did maximum keratometry from 42.40 to 42.00 D pre-ufCXL to post-ufCXL ( = .0420). The ufCXL demarcation line depth was 336 ± 21 µm post-ufCXL, with normal endothelial cell density (2,574 ± 203 cells/mm). Only 1 of 20 eyes showed evidence of progression of 1.00 D in maximum keratometry.
The ufCXL procedure shows promise in stabilizing early post-LASIK ectasia. Visual function, refractive astigmatism, maximum keratometry, and corneal irregularity indices were statistically maintained at 36 months postoperatively. .
研究瓣下基质交联（ufCXL）的 36 个月临床结果，并报告其稳定激光原位角膜磨镶术（LASIK）后扩张的能力。
本病例系列包括 20 只诊断为早期 LASIK 后扩张的眼睛，采用 ufCXL 治疗。纳入标准为早期、轻度 LASIK 后扩张，定义为新出现的术后角膜散光柱镜 1.50 屈光度（D）或更低，与扩张一致的新地形下陡变，未矫正远视力 20/40 或更好，矫正远视力 20/25 或更好。抬起现有的 LASIK 瓣，将 0.25%等渗核黄素直接应用于基质床，重新定位瓣，将 18 mW/cm 紫外线应用于角膜瓣表面 5 分钟。将 ufCXL 后的眼科数据与 ufCXL 前的基线测量值进行比较。
ufCXL 后的 36 个月内，视觉结果保持不变，安全性指数（=0.6545）、有效性指数（=0.4980）、球镜等效精度（=0.1536）、散焦等效精度（=0.1032）、中央角膜厚度（=0.5196）和 3mm（=0.8548）和 5mm（=0.3399）角膜不规则指数均保持不变。ufCXL 前的屈光性散光从 0.83 降低至 0.55 D（=0.0439），ufCXL 前的最大角膜曲率从 42.40 降低至 42.00 D（=0.0420）。ufCXL 标记线深度为 336±21µm，内皮细胞密度正常（2574±203 个/毫米）。仅 20 只眼睛中有 1 只显示最大角膜曲率增加 1.00 D 的证据。
ufCXL 程序在稳定早期 LASIK 后扩张方面显示出前景。术后 36 个月时，视觉功能、屈光性散光、最大角膜曲率和角膜不规则指数均得到统计学维持。
