Department of Ophthalmology, Kasr Al Ainy School of Medicine, Cairo University, Giza, Egypt.
Middle East Afr J Ophthalmol. 2021 Apr 30;28(1):11-17. doi: 10.4103/meajo.MEAJO_186_20. eCollection 2021 Jan-Mar.
To evaluate the efficacy and safety of epithelial-island crosslinking (EI-CXL) in keratoconus with corneas thinner than 400 µm.
Twenty-six patients (30 eyes) underwent EI-CXL (preserving the epithelium over the thinnest area), using standard protocol (3 mW/cm for 30 min). Uncorrected and best spectacle-corrected distance visual acuity (UCDVA, BCDVA), manifest refractive spherical equivalent (SEQ), mean simulated keratometry (Kmean), maximum keratometry (Kmax), and thinnest corneal thickness (TCT) were determined preoperatively and at 1, 3, 6, and 12 months following CXL. Endothelial cell count (ECC) was determined preoperatively and at 6 months. Anterior segment optical coherence tomography (AS-OCT) was done at 1 month to determine the depth of the corneal stromal demarcation line (DL).
After 1 year, mean UCDVA improved from 1.29 preoperatively to 1.17 ( = 0.001) and BCDVA from 0.62 to 0.57 ( = 0.011). Mean manifest SEQ decreased from -7.63 to-7.32D ( = 0.001). Mean Kmean decreased from 54.92 to 54.81D ( = 0.045), and Kmax from 67.60 to 67.42D ( = 0.072), and mean TCT changed minimally from 377.17 to 375.30 µ ( = 0.11). The mean ECC decreased from 2329 to 2268 cells/mm (2.6% decrease, < 0.001). AS-OCT showed a DL in 29 out of 30 eyes at an average depth of 215.9 µ under the spared epithelium, and 299.9 µ in the de-epithelialized cornea.
EI-CXL halted keratoconus progression over a 1-year period. This was associated with statistically significant endothelial loss, but less than seen with conventional epi-off CXL in thinner corneas.
评估上皮岛交联术（EI-CXL）在角膜厚度小于 400µm 的圆锥角膜中的疗效和安全性。
26 名患者（30 只眼）接受 EI-CXL（保留最薄区域的上皮），采用标准方案（3mW/cm 照射 30 分钟）。在手术前以及术后 1、3、6 和 12 个月，分别检测未矫正和最佳矫正远距视力（UCDVA、BCVA）、眼前节光学相干断层扫描（AS-OCT）、等效球镜（SEQ）、平均模拟角膜曲率（Kmean）、最大角膜曲率（Kmax）和最薄角膜厚度（TCT）。在手术前和 6 个月检测内皮细胞计数（ECC）。术后 1 个月行 AS-OCT 以确定角膜基质分界线（DL）的深度。
术后 1 年，平均 UCDVA 从术前的 1.29 提高到 1.17（=0.001），BCVA 从 0.62 提高到 0.57（=0.011）。平均 SEQ 从-7.63 降低到-7.32D（=0.001）。平均 Kmean 从 54.92 降低到 54.81D（=0.045），Kmax 从 67.60 降低到 67.42D（=0.072），平均 TCT 从 377.17µ 变化不大，为 375.30µ（=0.11）。平均 ECC 从 2329 减少到 2268 个细胞/mm（减少 2.6%，<0.001）。AS-OCT 显示 30 只眼中的 29 只在保留上皮下的平均深度为 215.9µ 处出现 DL，在去上皮化角膜中为 299.9µ。
EI-CXL 在 1 年内阻止了圆锥角膜的进展。这与统计学上显著的内皮细胞损失相关，但在较薄的角膜中，与传统的 epi-off CXL 相比，损失较少。
