Ultrastructural changes of corneal stromal lenticule after laser shaping

With the aim to improve the application of stromal lenticules derived from small-incision lenticule extraction (SMILE) surgery in treating refractive and corneal diseases, a technique was developed in the present study to reshape these lenticules by modifying their thickness distribution. For this, the ultrastructural changes in SMILE-derived corneal stromal lenticules following excimer laser reshaping were examined. SMILE was performed on 40 myopia using the VisuMax femtosecond laser system. In the experimental group, 20 corneal stromal lenticules were reshaped using an excimer laser, while the remaining 20 lenticules were left untreated as the control group. A total of 14 lenticules from both groups were used to measure changes in absorbance and light transmittance, while six from each group were histologically examined by HE staining and evaluation under an optical microscope to assess their morphological structure. No visible edema was observed in the central cornea before or after laser reshaping, and the stromal fiber layers remained regularly arranged. No abnormalities were found in the two groups. A significant improvement in lenticule light transmittance was observed after reshaping. In conclusion, excimer laser plasticity did not alter the regular arrangement of corneal stromal lenticule fibers but significantly enhanced their light transmittance.