Corresponding Author

Zayan, Ibrahim

Document Type

Original Article


Background: Small-incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (FS-LASIK) are the most recent vision correction techniques. In SMILE procedures a stromal lentiform slice is designed by femtosecond laser then extracted manually. Theoretically SMILE safeguards the corneal biomechanics more than FS-LASIK due to its smaller incisions and reservation of anterior corneal stromal collagen. Aim of the study: Our aim was to compare the corneal biomechanical changes induced by FS-LASIK and SMILE procedures using dynamic Scheimpflug imaging (Corvis-ST). Patients and Methods: This was a prospective comparative observational study, with 80 eyes were included. 40 eyes were subjected to FS-LASIK procedures and 40 eyes were subjected to SMILE procedures. We analyzed the preoperative and the postoperative Corvis ST parameters for both groups over a period of one year in the IFLC in Cairo. Results: The two studied groups were comparable in respect to the first and second applanation parameters showing no significant difference. Also, both groups were comparable in respect to changes in mean deformation, peak distance and radius after one year follow up. Conclusion: Corneal biomechanical properties were substantially decreased after both procedures as regarding preoperative and postoperative data, with no significant difference between both groups.


SMILE; FS-LASIK; Corvis ST; corneal biomechanics