AIM: To report the long-term clinical outcomes of accelerated trans-epithelial corneal cross-linking(CXL)protocols using KXL System(Avedro, USA)in the treatment of progressive keratoconus.

METHODS: Totally 52 patients(102 eyes)with progressive keratoconus between December 2014 and February 2017 \〖maximum keratometry values(Kmax)≤60.0D, minimum corneal thickness(Thk)≥400m\〗 were treated with an accelerate trans-epithelial CXL protocol(UV-A irradiation intensity 45mW/cm² with a total fluence of 7.2J/cm²)using KXL system(Avedro, USA)in Southwest Hospital. The average follow-up time was 11.65mo(range: 9-26mo). Uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), intra-ocular pressure(IOP), slit-lamp microscope examination, Kmax and average keratometry values(AveK), corneal stromal demarcation line depth and endothelial cell density(ECD)were evaluated.

RESULTS: The 52 patients(102 eyes)were included in this research, male 36(70 eyes)and female 16(32 eyes), average age was 19.5±4.6 years. Preoperative CDVA was 0.84±0.89(LogMAR), postoperative CDVA was 0.69±0.72(P=0.398). Preoperative UDVA was 1.02±0.62(LogMAR), postoperative UDVA was 0.85±0.59(P=0.154). Preoperative IOP was 12.95±4.40mmHg, postoperative IOP was 11.92±3.66mmHg(P=0.272). No statistical difference(P=0.552)has been found between preoperative and postoperative ECD. Nevertheless, on the Sirius anterior system(Sirius, CSO, Itlay), significant statistical difference(P=0.017)was confirmed between preoperative Kmax(50.83±3.48D)and postoperative Kmax(52.05±3.63D). Meanwhile, the postoperative Avek(47.74±2.51D)was significantly lower(P=0.041)than the preoperative Avek(48.73±4.33D). The average corneal stromal demarcation line depth(192±23.6μm)was detected by the anterior segment OCT. No statistical difference(P=0.816)has been found between preoperative and postoperative Thk. No severe complication was observed in all cases.

CONCLUSION: Accelerated trans-epithelial CXL was effective in decreasing keratometry values for progressive keratoconus in this research, and the outcomes remained stable during the follow-up time. No endothelium damage or other severe complications were observed in this clinical research. The accelerated trans-epithelial CXL is as effective as the standard CXL.