Early Corneal Wound Healing And Inflammatory Response After Femtosecond Lenticule Extraction (FLEx) Procedure

1. Andri Riau¹
2. Shyam Chaurasia¹
3. Romesh Angunawela^1,2
4. Roger Beuerman^1,3,4
5. Jodhbir Mehta^1,2,4

¹Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
²Singapore National Eye Centre, Singapore
³Department of Ophthalmology, National University of Singapore, Singapore
⁴Duke-NUS Graduate Medical School, Singapore

Purpose: To study and compare the corneal wound repair response and inflammation changes after femtosecond lenticule extraction (FLEx) and LASIK.

Methods: Nine rabbits in each group underwent FLEx and LASIK procedure. In each group, each 3 rabbits were subjected to different power of correction: -3.00D, -6.00D, and -9.00D. Follow-up examinations, such as slit lamp, AS-OCT, keratography, and in vivo confocal microscopy were performed 1 day after surgery. After sacrifice, the corneas were subjected to immunofluorescent staining of fibronectin, CD11b, and Ki-67. Nuclear DNA fragmentation was detected using the TUNEL assay.

Results: Under slit lamp, the cornea appeared clear with a visible flap sidecut mark in both post-FLEx and LASIK eyes. Corneal flattening was observed after both procedures with decreasing K-value as the power of correction was increased. However, there was no significant difference in K-value between post-FLEx and LASIK corneas. Using in vivo confocal microscopy, less light scattering and inflammatory cells were seen at the keratotomy site of post-FLEx than that of post-LASIK. Immunostaining of fibronectin and CD11b showed a less abundant expression in the cornea that underwent FLEx. This phenomenon may imply that there was less corneal wound healing action required after FLEx if compared to LASIK. The differences became more distinct as the power of correction was increased. There was no marked disparity observed in the immunostaining of Ki-67 and the TUNEL assay.

Conclusions: Our results have shown that FLEx procedure may cause less inflammation and have favorable wound healing response than LASIK especially at high refractive correction.