<p>Comparison Between the Effect of Femtosecond Laser in situ Keratomileusis (FS-LASIK) and Femtosecond Small Incision Lenticule Extraction (FS-SMILE) on the Corneal Endothelium</p>

Abstract

Purpose: To compare the effect of FS-LASIK and FS-SMILE on the corneal endothelial cell density (ECD) and morphology. Patients and Methods: This is a prospective, cohort observational study that included 80 eyes of two equal groups of patients. Forty eyes were subjected to the FS-LASIK, and 40 eyes were subjected to the FS-SMILE. In both groups, patients, age ranged between 19 and 37 years with myopia ranges from −0.75 to −9.00 diopters (D) and astigmatism up to −3.00D. The ECD, coefficient of variation (CV), and hexagonality (HEX) in both groups were compared over six months. Specular microscopy was used to evaluate the corneal endothelium throughout the study. Results: In both groups, ECD showed a statistically significant decrease while CV showed a statistically significant increase in the first month postoperatively. The FS-SMILE had more impact on both ECD and CV until the third and six months, respectively. Hexagonality showed a significant decrease in both groups throughout the whole study. In both groups, no vision-threatening complications occurred, and no eyes developed any corneal complications over a six-month follow-up period. Conclusion: Although the ECD, CV, HEX are statistically affected in both FS-LASIK and FS-SMILE groups, both procedures have no significant adverse effects on the ECD and morphology. The impact of the FS-SMILE group may be due to the deeper penetration of the femto laser in the corneal tissue compared to the FS-LASIK. The closer the femto laser to the endothelium, the more exposure to the shock waves and heat energy, although minimal but it can cause collateral damage to this layer. The effects of FS-SMILE surgery on corneal endothelial cells and morphology need further investigations.

Evaluation of the Effect of Myopic Femtosecond Laser Assisted-LASIK on Anterior Chamber Flare Values and Corneal Endothelial Cells: A Prospective Before-and-After Study

“…These ndings suggest that endothelial cells may be trying to compensate for the decrease in ECD via polymegatism. Similar to our study, a recently published study by Shaaban et al [29] reported a statistically signi cant decrease in ECD and a change in endothelial morphology, although clinically insigni cant in both FS-LASIK and small incision lenticule extraction (SMILE). The effect on the endothelial cells may be related to the heat energy generated by the shock waves that occur when the ap is created with the FS laser.…”

Effect of Myopic Femtosecond Laser-Assisted LASIK on Anterior Chamber Inflammation (Flare Values) and Corneal Endothelium: A Prospective before and after Study

“…Durrie et al [28] compared PRK with thin-flap LASIK and reported no significant changes in the ECD at the 3 rd postoperative month with both techniques and no difference between the two techniques. However, similar to us, a recently published study by Shaaban and Badran [29] reported a statistically significant decrease in ECD and a mild change in endothelial morphology, although clinically insignificant in both FS-LASIK and small incision lenticule extraction (SMILE).…”

Clinical Evaluation of Corneal Endothelial Parameters following Laser Refractive Surgery in Myopic Eyes: A Review

“…Eleven studies focused on PRK only, one study focused on LASEK [ 22 ], one focused on Trans-PRK [ 23 ], two focused on LASIK or FemtoLASIK [ 24 , 25 ], and two analyzed SMILE [ 26 , 27 ]. Seven remaining studies were comparative trials, three studies focused on PRK and LASIK [ 28 , 29 , 30 ], one focused on PRK and LASEK [ 31 ], one focused on PRK and Epi-LASIK [ 32 ], one focused on LASIK and FemtoLASIK [ 33 ], and one analyzed FemtoLASIK and SMILE [ 34 ]. Five studies explored PRK or LASEK with an intraoperative 0.02% MMC application [ 22 , 23 , 32 , 35 , 36 ].…”