AIM: To observe the epithelial remodeling of femtosecond laser-assisted stromal lenticule addition keratoplasty combined with corneal collagen cross-linking(SLAK-CXL)in patients with progressive keratoconus, investigate the remodeling rules of corneal epithelial and influencing factors, and provide clinical data for further refractive correction.

METHODS: Retrospective and observational study. A total of 28 keratoconus patients(29 eyes)who received SLAK-CXL from September 2020 to October 2021 were included. Preoperative and postoperative visual acuity, intraocular pressure(IOP), diopter, keratometry and corneal epithelial thickness(CET)were recorded. The trend of CET change was observed. The factors affecting CET were analyzed according to the thickness and depth of the lenticule.

RESULTS: Flattest meridian keratometry(K_f)and steepest meridian keratometry(K_s)at 1mo postoperatively were significantly larger than those preoperatively(P<0.05). The thinnest corneal thickness(TCT)at 1, 2, 6mo and 1a postoperatively were significantly larger than preoperative(P<0.05). The CET changed with time, with the central CET showing a larger variation tendency. The CET of superior, superior nasal, nasal, superior temporal in paracentral area were thinned, the CET of superior, temporal, superior temporal in midperipheral area were thinned, while the CET of superior nasal was thickened in peripheral area at 1, 2, 6mo and 1a postoperatively. The variation of CET was not correlated with the thickness or depth of lenticule at 1a postoperatively(P>0.05).

CONCLUSIONS: It is firstly found that the corneal morphology has changed after SLAK-CXL. CET decreases and then increases and then decreases again. At 1a postoperatively, the CET of the central and paracentral areas is thinner, while the CET of the midperipheral and peripheral areas is thicker. The degree of epithelial remodeling is not correlated with lenticule thickness or depth.