AIM: To evaluate the safety and efficacy of allogeneic intrastromal lenticule implantation combined with corneal collagen cross-linking(CXL)in patients with moderate to advanced keratoconus.

METHODS: A retrospective case series analysis was conducted. A total of 19 patients(20 eyes)with moderate to advanced keratoconus who underwent combined allogeneic intrastromal lenticule implantation and CXL at the Jinan Mingshui Eye Hospital from June 2021 to December 2023 were included. The uncorrected distance visual acuity(UCVA), thinnest corneal thickness, central corneal epithelial thickness, anterior corneal flat keratometry(Kf), steep keratometry(Ks), and mean keratometry(Km), as well as the first applanation time(A1T), the first applanation length(A1L), the velocity during the first applanation moment(VIN), the second applanation time(A2T), the second applanation length(A2L), the velocity during the second applanation moment(VOUT), highest concavity time(HCT), highest concavity radius(HCR), peak distance(PD), deformation amplitude(DA), stiffness parameter at first applanation(SP-A1), integrated radius(IR), central corneal thickness(CCT), intraocular pressure(IOP), corneal thickness-corrected IOP, biomechanically intraocular pressure IOP(bIOP), and corneal thickness variation rate(ARTH)were compared between the two groups before surgery and at 1 wk, 1, 3 and 6 mo after surgery.

RESULTS: All patients successfully completed the surgery without any intraoperative complications. No significant differences were observed between pre-operative and post-operative measurements for UCVA or the corneal biomechanical parameters, including A1L, A2L, PD, A1T, A2T, VIN, VOUT, DA, IOP, and bIOP(all P>0.05). Significant differences were found between pre-operative and post-operative values for corneal thinnest point thickness, central corneal epithelial thickness, Kf, Ks, Km, and the corneal biomechanical parameters, including HCT, HCR, SP-A1, ARTH, IR, and CCT(all P<0.05). The anterior corneal curvature demonstrated an initial increase followed by a decrease post-operatively. Furthermore, significant differences were observed between pre-operative and post-operative values for HCT, HCR, SP-A1, ARTH, IR, and CCT(all P<0.005).

CONCLUSION: Allogenic intrastromal lenticule implantation combined with corneal collagen cross-linking demonstrates favorable safety and stability in treating moderate-to-advanced keratoconus. This combined procedure effectively increases corneal thickness and rigidity, resulting in corneas that are more resistant to deformation postoperatively.