Evaluation of Human Corneal Lenticule Quality After SMILE With Different Cap Thicknesses Using Scanning Electron Microscopy

Abstract

There is smoother appearance of the lenticular surface as seen through SEM when a thin cap is created compared with a thick cap qualitatively and quantitatively.

A microscopic study of the corneal stromal lenticules extracted during femtosecond laser‑assisted small incision lenticule extraction

“…In addition to the influence of existing bubbles, other factors, including the laser parameters (26-28), surgical technique (29,30), cap thickness (31)(32)(33) and mechanical separation (34), may also affect the surface smoothness. For instance, Kunert et al (26) reported that the surface regularity of corneal lenticules tends to decrease with the increase in laser energy.…”

“…Serrao et al (27) demonstrated that the stromal interface quality may be improved by decreasing the pulse energy and spot distance. In addition, it has been noticed that a smooth appearance of the lenticular surface exists when a thin cap or a shallow ablating depth is created (31)(32)(33). When a laser beam passes through a thick corneal tissue, the focus of the beam is distorted and this weakens the laser efficacy; therefore, additional tissue bridges are created and these make the ablating surface more irregular.…”

“…Similar to a previous study (31), the cap thickness was set as 120 µm and microscopes were used to observe the lenticule surface quality in the present study. To determine the histological and morphological characteristics of the lenticules, H&E staining was applied to help observe the changes of collagen fibers and scoring criteria for evaluating the smoothness from the SEM images were applied.…”

Corneal aberrations after small-incision lenticule extraction versus Q value-guided laser-assisted in situ keratomileusis

“…Compared to the femtosecond laser, the ablation done by the excimer laser can yield a smoother surface, which needs a relatively shorter repair time. [36] Finally, under the same diopter, SMILE consumes more corneal tissue, which makes the change of corneal shape more obvious because SMILE needs to remove a layer of ineffective stroma. A previous study showed that compared with Q-FS-LASIK, SMILE induced less total HOA, but induced more horizontal and vertical coma.…”

Corneal aberrations after small-incision lenticule extraction versus Q-value-guided laser-assisted in situ keratomileusis

“…However, after removing a large number of corneal stroma, compared to corneal cap of SMILE, the corneal flap of Q-FS-LASIK should have a better fit with the remaining corneal stroma; 4.) compared to the femtosecond laser blasting, the ablation done by the excimer laser can yield a smoother surface, which need a relatively shorter repair time [21]; and 5.) under the same diopter, SMILE consumes more corneal tissue, which make the change of corneal shape more obvious because SMILE needs to remove a layer of ineffective stroma.…”