Corneal stability of LASIK and SMILE when combined with collagen cross-linking

Aris Konstantopoulos, Yu-Chi Liu, Ericia P. Teo, Chan L. Nyein, Gary H. Yam, Jodhbir S. Mehta

Research output: Contribution to journalArticlepeer-review

5 Downloads (Pure)


Purpose: We investigate whether small incision lenticule extraction (SMILE) is associated with less ectasia than laser-assisted in-situ keratomileusis (LASIK) and whether concomitant collagen cross-linking (CXL) is protective in SMILE Xtra and LASIK Xtra.

Methods: Using an established LASIK rabbit ectasia model, we performed -5 diopter (D) LASIK on six eyes and -5 D SMILE on six eyes; five eyes had -5 D LASIK Xtra, five eyes -5 D SMILE Xtra. Anterior segment optical coherence tomography and corneal topography were performed preoperatively and 2, 4, and 6 weeks postoperatively. Mean (standard deviation [SD]) values of postoperative keratometry (K), maximum posterior elevation (MPE) and minimum corneal thickness (CT) were compared to preoperatively and among the surgical groups (paired t-test, analysis of variance).

Results: Mean (SD) K values decreased significantly following SMILE, SMILE Xtra, LASIK, and LASIK Xtra. The MPE increased significantly (P < 0.05) following LASIK, SMILE, and SMILE Xtra, but not following LASIK Xtra (P = 0.12). The MPE was less following SMILE than LASIK, but not statistically significant (week 2, 17.73 [5.77] vs. 22.75 [5.05] μm; P = 0.13); post-LASIK Xtra MPE was less than that following LASIK (week 2. 13.39 [3.05] vs. 22.75 [5.05] μm; P < 0.001). CT decreased significantly in all surgical groups; no differences were detected among the groups.

Conclusions: SMILE may have less potential than LASIK to induce ectasia. LASIK Xtra and SMILE Xtra showed the smallest increase in MPE.Translational relevance: Concomitant CXL may be protective following keratorefractive surgery and may reduce further the risk of ectasia.
Original languageEnglish
Article number21
Number of pages11
JournalTranslational Vision Science & Technology
Issue number3
Publication statusPublished - 1 May 2019


  • collagen cross-linking
  • ectasia
  • LASIK Xtra


Dive into the research topics of 'Corneal stability of LASIK and SMILE when combined with collagen cross-linking'. Together they form a unique fingerprint.

Cite this