Akbar Bushra, Intisar-Ul-Haq Rana, Ishaq Mazhar, Fawad Ayesha, Arzoo Sabahat, Siddique Kashif
Department of Ophthalmology, Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan.
Biostatistics, King Salman Armed Forces Hospital, Tabuk, KSA Academic Affairs (Research Unit), Saudi Arabia.
Taiwan J Ophthalmol. 2017 Oct-Dec;7(4):185-190. doi: 10.4103/tjo.tjo_38_17.
The purpose of this study is to compare the safety and efficacy of transepithelial corneal crosslinking (CXL) with epithelium-off crosslinking (epithelium-off CXL) in the treatment of progressive keratoconus in adult Pakistani population.
Sixty-four eyes of 64 consecutive patients of progressive keratoconus were included in this quasi-experimental study. Thirty-two eyes received transepithelial CXL with Peschke TE (0.25% riboflavin (Vitamin B2), 1.2% hydroxypropyl methylcellulose (HPMC), 0.01% benzalkonium chloride) and 32 eyes received epithelium-off CXL with Peschke M (0.1% riboflavin (Vitamin B2) 0.1%, HPMC 1.1%.) The cornea was then exposed to ultraviolet A light at an irradiance of 3 mW/cm for 30 min. The primary outcome measure, clinical stabilization of keratoconus was defined as an increase of no more than 1D in K at 1 year. Other parameters evaluated at baseline and 3, 6, 12, and 18 months postoperatively were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent (SE), astigmatism (Ast), simulated keratometry, steep keratmetry (steep K), and corneal thickness at thinnest point (pachy thin).
Both epithelium-off CXL and transepithelial CXL groups showed a significant reduction in K, steep K, simulated K, corneal pachymetry at all test points ( < 0.05) with significantly greater reductions achieved in epithelium-off CXL group at 18 months follow-up. The mean UDVA, CDVA, SE, Ast significantly improved in both groups ( < 0.05). The mean postoperative UDVA and CDVA between the groups were not significant at 12 months ( = 0.650, 0.018, respectively). Clinical stabilization was achieved in 94% of eyes in epithelium-off CXL and 75% of eyes in transepithelial CXL. In epithelium-off CXL, three eyes exhibited stromal haze resolved by corticosteroid treatment. No complication was documented in transepithelial CXL group.
Transepithelial CXL is not recommended to be replaced completely by standard epithelium-off CXL due to continued ectatic progression in 25% of cases. However, thin corneas, unfit for standard epithelium-off CXL, can benefit from transepithelial CXL.
本研究旨在比较经上皮角膜交联术（CXL）与去上皮角膜交联术（去上皮CXL）在治疗成年巴基斯坦人群进展性圆锥角膜中的安全性和有效性。
本准实验研究纳入了64例连续的进展性圆锥角膜患者的64只眼。32只眼接受了使用Peschke TE（0.25%核黄素（维生素B2）、1.2%羟丙基甲基纤维素（HPMC）、0.01%苯扎氯铵）的经上皮CXL，32只眼接受了使用Peschke M（0.1%核黄素（维生素B2）、0.1% HPMC、1.1%）的去上皮CXL。然后将角膜暴露于辐照度为3 mW/cm²的紫外线A光下30分钟。主要结局指标，圆锥角膜的临床稳定定义为1年后角膜曲率（K）增加不超过1D。在基线以及术后3、6、12和18个月评估的其他参数包括未矫正远视力（UDVA）、矫正远视力（CDVA）、等效球镜度（SE）、散光（Ast）、模拟角膜曲率、陡峭角膜曲率（陡峭K）以及最薄点处的角膜厚度（最薄角膜厚度）。
去上皮CXL组和经上皮CXL组在所有测试点的K、陡峭K、模拟K、角膜测厚均显著降低（P<0.05），在18个月随访时去上皮CXL组降低更为显著。两组的平均UDVA、CDVA、SE、Ast均显著改善（P<0.05）。两组间术后12个月时的平均UDVA和CDVA无显著差异（分别为P = 0.650、0.018）。去上皮CXL组94%的眼实现了临床稳定，经上皮CXL组75%的眼实现了临床稳定。在去上皮CXL组中，三只眼出现基质 haze，经皮质类固醇治疗后消退。经上皮CXL组未记录到并发症。
由于25%的病例存在持续的扩张进展，不建议完全用标准的去上皮CXL替代经上皮CXL。然而，对于不适合标准去上皮CXL的薄角膜，经上皮CXL可能有益。
