Comparison of the Effects of Femtosecond Laser Energy on Corneal Endothelium at Two Different Dissection Levels in Femtosecond Laser Assisted Deep Anterior Lamellar Keratoplasty for Keratoconus Patients

Abstract

Keratoconus is a non-inflammatory progressive corneal dystrophy, characterized by thinning and ectasia of the corneal stroma, which results in the development of progressive myopia and irregular astigmatism. DALK is considered the ‘gold standard’ for management of advanced cases of keratoconus. It achieves comparable visual outcomes to PK but with a superior safety profile. It selectively replaces the diseased host corneal stroma while preserving the healthy endothelium. Hence, it abolishes the risk of endothelial rejection and prolongs graft survival. Successful exposure of DM is essential to optimize visual outcomes in DALK. The big-bubble technique made the exposure of DM easier and less time-consuming. The use of FSL in DALK added the advantage of precision and reproducibility to the procedure. The precise depth of the laser-assisted cuts might increase the chances of successful DM baring by the big-bubble technique. The potential notorious effect of FSL energy on the corneal endothelium when applied in close proximity to the DM is an under studied subject. Our study showed that the endothelial safety profiles of lamellar FSL cuts applied at 110 µm or 80 µm anterior to the DM at the thinnest location are comparable. Cuts as deep as 80 µm anterior to the DM can be safely applied without causing significant injury to the endothelium.