AIM: To compare the early results of different kinds of transepithelial corneal collagen cross-linking(TE-CXL)in the treatment of progressive keratoconus.

METHODS: Retrospective study. Twenty four patients(34 eyes)who were diagnosed with progressive keratoconus were divided into three groups. And 10 eyes in hypotonic CXL group received the treatment of hypotonic corneal collagen cross-linking; 14 eyes in I-CXL 5min group received the treatment of iontophoresis corneal collagen cross-linking for 5min, and 10 eyes from the I-CXL 10min group received the treatment of iontophoresis corneal collagen cross-linking for 10min. Uncorrected distance visual acuity, corrected distance visual acuity, Pentacam, in vivo scanning laser confocal microscopy and anterior segment optical coherence tomography were examined before and after 1wk, 1, 3 and 6mo postoperatively.

RESULTS: Six months postoperatively, corrected distance visual acuity(CDVA)(LogMAR)in I-CXL 10min group increased by -0.21±0.23(t=2.735, P=0.026); Kmax decreased by 2.32±5.21D(t=1.40,P=0.193), but the differences were not statistically significant. Uncorrected distance visual acuity(UDVA), CDVA and Kmax in hypotonic CXL group and I-CXL 5min group were stable, the differences were not statistically significant. The depth of demarcation line was 152.7±42.9μm in hypotonic CXL group, 213.6±42.3μm in I-CXL 5min group and 237.0±46.4μm in I-CXL 10min group 1wk after the surgery, the differences among groups were statistically significant(F=7.111, P=0.006).The phenomenon of stroma cell apotosis-activate-regeneration in I-CXL 10min group was the most significant after the surgery. The changes of corneal thinnest thickness and endothelial cell density in three groups were stable.

CONCLUSION: Three kinds of transepithelial CXL can halt the progression of keratoconus, among which the reaction of corneal tissue in iontophoresis CXL for 10min is the most obvious.