Short-Term Observation Of Corneal Morphological Parameters And Aberration In Keratoconus Treated With Allogeneic Stromal Lenticule Implantation At Different Depths Combined With Corneal Cross-Linking

To investigate the short-term effects of femtosecond laser-assisted allogeneic corneal stromal lenticule implantation combined with rapid corneal collagen cross-linking (SLAK-CXL) on corneal morphological parameters and aberration in patients with moderate to advanced keratoconus, considering different implantation depths.

This retrospective study collected data from 88 patients (88 eyes) who underwent SLAK-CXL at the Laser Vision Center of Xi’an No.1 Hospital. The cohort consisted of 66 males and 24 females aged 12–49 years. Patients were divided into a superficial group (Group1, <46.99%) and a deep group (Group2, ≥46.99%) based on the median ratio of lenticule implantation depth to minimal corneal thickness.

Corneal morphological parameters, including anterior and posterior symmetry index(SIf, SIb), highest point keratoconus vertex(KVf, KVb), apical keratoscopy(AKf, AKb),best-fit combined aberration vector(BCVf, BCVb), and root mean square values(RMSfA, RMSbA), were measured preoperatively and at 1, 3, and 6 months postoperatively. Trends over time were analyzed using repeated-measures ANOVA, and intergroup differences were assessed with independent sample t-tests. A simple linear regression analysis was used to evaluate the effect of implantation depth on postoperative changes in each parameters. 

1.In the total sample group, SIf, SIb, KVb, and AKb decreased significantly at 6 months compared to preoperative values (all P<0.05), while AKf increased (P<0.05). In Group1, KVf increased (P<0.05) and KVb decreased (P<0.05) at 6 months compared to preoperative values. In Group2, AKf increased (P<0.05), while SIf, SIb, KVb decreased (all P<0.05). Intergroup comparison revealed a significant difference in KVb at 6 months (P<0.05).2.BCVf, BCVb, and RMSfA in the total sample showed significant changes over time (P<0.05). At 6 months, BCVb decreased significantly within each group (P<0.05).3.At 6 months, KVf and BCVf increased in Group1, but decreased in Group2, with significant intergroup differences (both P<0.05).

SLAK-CXL effectively improves corneal morphology parameters and aberration in moderate to advanced keratoconus. Deeper implantation depths lead to more pronounced improvements in corneal morphological parameters, providing a foundation for future personalized lenticule implantation designs.